0000719451 fas6:S000005156Member 2012-01-30 2013-01-29 0000719451 2012-01-30 2013-01-29 0000719451 fas6:S000005156Member fas6:C000014122Member 2012-01-30 2013-01-29 0000719451 fas6:S000005156Member rr:AfterTaxesOnDistributionsMember fas6:C000014122Member 2012-01-30 2013-01-29 0000719451 fas6:S000005156Member rr:AfterTaxesOnDistributionsAndSalesMember fas6:C000014122Member 2012-01-30 2013-01-29 0000719451 fas6:S000005156Member fas6:BarclaysUsOneFiveYearGovernmentBondIndexMember 2012-01-30 2013-01-29 0000719451 fas6:S000005156Member fas6:ReturnBeforeTaxesMember fas6:C000014122Member 2012-01-30 2013-01-29 pure iso4217:USD <div style="display:none">~ http://www.fidelity.com/role/ScheduleShareholderFeesFidelityInstitutionalShort-IntermediateGovernmentFund column period compact * ~</div> 485BPOS 2012-11-30 2013-01-28 2013-01-29 2013-01-29 FIDELITY ADVISOR SERIES IV 0000719451 false Fund Summary Fund: Fidelity® Institutional Short-Intermediate Government Fund Investment Objective The fund seeks a high level of current income in a manner consistent with preserving principal. Fee Table The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund. Shareholder fees (fees paid directly from your investment) Annual fund operating expenses (expenses that you pay each year as a % of the value of your investment) This example helps compare the cost of investing in the fund with the cost of investing in other mutual funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated: Portfolio Turnover The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 138% of the average value of its portfolio. Principal Investment Strategies <ul><li>Normally investing at least 80% of assets in U.S. Government securities and repurchase agreements for those securities.</li><li>Investing in U.S. Government securities issued by entities that are chartered or sponsored by Congress but whose securities are neither issued nor guaranteed by the U.S. Treasury.</li><li>Investing in instruments related to U.S. Government securities.</li><li>Managing the fund to have similar overall interest rate risk to the Barclays® U.S. 1-5 Year Government Bond Index.</li><li>Normally maintaining a dollar-weighted average maturity between two and five years.</li><li>Allocating assets across different market sectors and maturities.</li><li>Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments.</li></ul> Principal Investment Risks <ul><li>Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.</li><li>Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.</li><li>Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.</li></ul>An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. You could lose money by investing in the fund. Performance The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the Additional Information about the Index section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. Visit www.fidelity.com for updated return information. Year-by-Year Returns Calendar Years <table border="1" width="95%"><tr><td><div align="left">During the periods shown in the chart: </div></td><td valign="bottom" align="center"><div align="center">Returns </div></td><td valign="bottom" align="center"><div align="center">Quarter ended</div></td></tr><tr><td><div align="left">Highest Quarter Return </div></td><td><div align="right">4.18% </div></td><td><div align="left">December 31, 2008</div></td></tr><tr><td><div align="left">Lowest Quarter Return </div></td><td><div align="right">-1.69% </div></td><td><div align="left">June 30, 2004</div></td></tr></table> Average Annual Returns After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement. Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares. For the periods ended December 31, 2012 0 0.0045 0 0 0.0045 46 144 252 567 0.0175 0.0131 0.0145 0.0365 0.0716 0.0794 0.0188 0.0333 0.0288 0.0092 0.0063 0.0066 0.0097 0.0092 0.0336 0.0257 0.0246 0.0339 0.032 0.0223 0.0219 0.0338 1.38 An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You could lose money by investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. Past performance (before and after taxes) is not an indication of future performance. www.fidelity.com After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement. Return Before Taxes Return After Taxes on Distributions Return After Taxes on Distributions and Sale of Fund Shares Barclays® U.S. 1-5 Year Government Bond Index Fidelity Institutional Short-Intermediate Government Fund Fidelity Institutional Short-Intermediate Government Fund Fidelity Institutional Short-Intermediate Government Fund <div style="display:none">~ http://www.fidelity.com/role/ScheduleAnnualTotalReturnsFidelityInstitutionalShort-IntermediateGovernmentFundBarChart column period compact * ~</div> Highest Quarter Return 2008-12-31 0.0418 Lowest Quarter Return 2004-06-30 -0.0169 <div style="display:none">~ http://www.fidelity.com/role/ScheduleAnnualFundOperatingExpensesFidelityInstitutionalShort-IntermediateGovernmentFund column period compact * ~</div> <div style="display:none">~ http://www.fidelity.com/role/ScheduleExpenseExampleFidelityInstitutionalShortIntermediateGovernmentFund column period compact * ~</div> <div style="display:none">~ http://www.fidelity.com/role/ScheduleAverageAnnualTotalReturnsTransposedFidelityInstitutionalShort-IntermediateGovernmentFund column period compact * ~</div> Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.