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<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2015 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2020 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2025 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2030 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2035 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2040 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2045 </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2050 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2015 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2015 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2020 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2020 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2025 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2025 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2030 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2030 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2035 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2035 Portfolio. </font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2040 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2040 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2045 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2045 Portfolio. </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2050 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2050 Portfolio. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td> <td valign="bottom"><font size="1"> </font></td></tr> <tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2015 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">44</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">56</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2020 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">54</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">46</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2025 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">62</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">38</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2030 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">69</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">31</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2035 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">76</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">24</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> </tr> <tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2040 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">82</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">18</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2045 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">88</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">12</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> <tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2050 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">93</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">7</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
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<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2015 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2015 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2015 Portfolio. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td> <td valign="bottom"><font size="1"> </font></td></tr> <tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2015 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">44</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">56</font></td><td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2020 </font></p><p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2020 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2020 Portfolio. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td> <td valign="bottom"><font size="1"> </font></td></tr> <tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2020 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">54</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">46</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2025 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2025 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2025 Portfolio. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2025 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">62</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">38</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2030 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2030 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2030 Portfolio.</font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2030 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">69</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">31</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2035 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2035 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2035 Portfolio.</font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2035 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">76</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">24</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2040 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2040 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2040 Portfolio.</font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2040 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">82</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">18</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2045 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2045 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2045 Portfolio.</font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2045 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">88</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">12</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>
<p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>BLACKROCK FUNDS II </b></font></p><p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">BlackRock Prepared Portfolio 2050 </font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>(each, a “Fund” and collectively, the “Funds”) </b></font></p> <p style="margin-top:12px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Supplement dated September 27, 2012 to the </font></p> <p style="margin-top:0px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2">Prospectus, dated February 28, 2012 </font></p> <p style="margin-top:12px;margin-bottom:0px;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">On September 11, 2012, the Board of Trustees (the “Board”) of BlackRock Funds II approved certain changes to the Funds. In particular, the Board approved a change in the name of the Funds to the “LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active Portfolios” and a change to each Fund’s “glide path,” which shows the target allocation among asset classes as a Fund approaches its target date. As a result of the change to the Funds’ glide path, each Fund’s current target allocation among asset classes is expected to change. Currently, the asset allocation of each Fund is expected to be 50% in underlying funds that invest primarily in equity and 50% in underlying funds that invest primarily in fixed income by its retirement date. Although each Fund’s target allocation may shift over time depending on market conditions, under the new glide path each Fund’s asset allocation is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income by its retirement date. Furthermore, in connection with the change to the Funds’ glide path, Fund management has determined to change the composition of the customized reference benchmark index against which each Fund measures its performance. </font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In addition, Fund management has determined to add the following funds as eligible underlying funds for the Funds: </font></p> <p style="margin-top:6px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares Cohen & Steers Realty Majors Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">iShares FTSE EPRA/NAREIT Developed Real Estate ex-U.S. Index Fund </font></p> <p style="margin-top:0px;margin-bottom:0px; margin-left:8%; text-indent:4%"><font style="font-family:ARIAL" size="2">BlackRock Commodity Strategies Fund </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The Board has also determined to redesignate each Funds’s Institutional Shares as Class K Shares. Fund fees and expenses are not expected to increase for current shareholders of each Fund’s Institutional Shares as a result of this redesignation. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">These changes will become effective on or about November 27, 2012. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Investors should review carefully the specific changes to the Prospectus of the Funds, reflecting the changes noted above, which are detailed below. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>Effective November 27, 2012, the following changes are made to the Prospectus of the Funds. </b></font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change in each Fund’s Name </u></i></font></p><p style="margin-top:0px;margin-bottom:0px; margin-left:4%; text-indent:4%;padding-bottom:0px;"><font style="font-family:ARIAL" size="2">The BlackRock Prepared Portfolio 2050 is renamed LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2050 Portfolio.</font></p> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Glide Path </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><b>The Prospectus is amended to reflect the following with respect to each Fund: </b></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following chart illustrates the glide path — the target allocation among asset classes as a Fund approaches its target date: </font></p> <p style="font-size:12px;margin-top:0px;margin-bottom:0px"> </p> <p style="margin-top:12px;margin-bottom:0px" align="center"><img alt="chart" src="g409282g409282g05u63.jpg"></img> </p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">Each Fund’s asset allocation will change over time according to a glide path, and is expected to become increasingly conservative until the Fund’s target retirement date. At the time a Fund reaches its target retirement date, the asset allocation of the Fund is expected to be 38% in underlying funds that invest primarily in equity and 62% in underlying funds that invest primarily in fixed income, and the target allocation may shift over time depending on market conditions. On approximately the target retirement date of a Fund, the Board may evaluate alternatives available to the Fund. These alternatives may include a merger into another BlackRock fund subject to the Board determining, among other things, that it would be in the best interest of the Fund. Such a merger may or may not require shareholder approval. Finally, the Board may instead cause the Fund to be liquidated. </font></p> <p style="margin-top:12px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">The following table illustrates each Fund’s current target allocation among asset classes: </font></p> <p style="margin-top:18px;margin-bottom:0px" align="center"><font style="font-family:ARIAL" size="2"><b>Target Asset Allocation </b></font></p> <div style="font-size:12px;margin-top:0px;margin-bottom:0px"> </div> <table cellspacing="0" cellpadding="0" width="100%" border="0" style="BORDER-COLLAPSE:COLLAPSE" align="center"> <tr> <td width="70%"></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td> <td valign="bottom" width="14%"></td> <td></td> <td></td> <td></td></tr> <tr> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Equity Funds<br/>(includes REITs<br/>and commodity<br/>funds)</b></font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom" colspan="2" align="center" style="border-bottom:1px solid #000000"><font style="font-family:ARIAL" size="1"><b>Fixed Income Funds</b></font></td></tr><tr bgcolor="#cceeff"> <td valign="top"> <div style="margin-left:1.00em; text-indent:-1.00em"><font style="font-family:ARIAL" size="2">LifePath<font style="font-family:ARIAL" size="1"><sup style="vertical-align:baseline; position:relative; bottom:.8ex">®</sup></font> Active 2050 Portfolio</font></div></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">93</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td> <td valign="bottom"><font size="1"> </font></td> <td valign="bottom"><font style="font-family:ARIAL" size="2"> </font></td> <td valign="bottom" align="right"><font style="font-family:ARIAL" size="2">7</font></td> <td nowrap="nowrap" valign="bottom"><font style="font-family:ARIAL" size="2">% </font></td></tr> </table> <p style="margin-top:18px;margin-bottom:0px"><font style="font-family:ARIAL" size="2"><i><u>Change to each Fund’s Reference Index </u></i></font></p> <p style="margin-top:6px;margin-bottom:0px"><font style="font-family:ARIAL" size="2">In connection with the change to the Funds’ glide path noted above, Fund management has determined to change the composition of the customized weighted index against which each Fund measures its performance. Currently, each Fund measures its performance against a customized weighted index comprised of the Barclays US Aggregate Bond Index, the Russell 3000 Index, and the MSCI EAFE Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Effective November 27, 2012, each Fund will measure its performance against a customized weighted index comprised of the Russell 1000 Index, Russell 2000 Index, MSCI ACWI ex US IMI Index, FTSE EPRA/NAREIT Developed Real Estate Index, Dow Jones UBS Commodity Index, Barclays US Aggregate Bond Index and Barclays TIPs Index, reflecting the investment adviser’s change of these indices’ weightings over time, which are adjusted periodically with its evaluation and adjustment of a Fund’s asset allocation strategy. Fund management believes the new composition of the customized weighted index is more relevant to each Fund’s new glide path. </font></p>