0000276914 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000018473Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000018474Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000018475Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000054855Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000018477Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000018476Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000054856Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:C000054857Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member rr:AfterTaxesOnDistributionsMember cik0000276914:C000018473Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member rr:AfterTaxesOnDistributionsAndSalesMember cik0000276914:C000018473Member 2012-07-31 2012-07-31 0000276914 cik0000276914:S000006834Member cik0000276914:index_Russell_2000_Growth_Index_reflects_no_deduction_for_fees_expenses_or_taxesMember 2012-07-31 2012-07-31 xbrli:pure iso4217:USD A contingent deferred sales charge ("CDSC") of 1.00% may be assessed on certain Class A shares purchased or acquired without a sales charge if they are redeemed before the first day of the month of the one-year anniversary of the purchase. A CDSC of 1.00% may be assessed on Class C shares if they are redeemed before the first anniversary of their purchase. This amount has been updated from fiscal year amounts to reflect current fees and expenses. LORD ABBETT DEVELOPING GROWTH FUND, INC. 485BPOS false 0000276914 2012-07-31 2012-11-27 2012-12-01 2012-12-01 LORD ABBETT DEVELOPING GROWTH FUND INC /NEW/ PRINCIPAL INVESTMENT STRATEGIES To pursue its objective, the Fund invests primarily in the common stocks of companies demonstrating above-average, long-term growth potential. The Fund seeks to identify companies that it believes are strongly positioned in the developing growth phase, which the Fund defines as the period of swift development after a company’s start-up phase when growth occurs at a rate rarely equaled by established companies in their mature years. Under normal market conditions, the Fund invests at least 65% of its net assets in equity securities of small companies. In selecting investments, the Fund may invest in U.S. and foreign (which may include emerging market) companies. Foreign companies may be traded on U.S. or non-U.S. securities exchanges, may be denominated in the U.S. dollar or other currencies, and may include American Depositary Receipts (“ADRs”). Although the Fund is diversified across many industries and sectors, its assets may, from time to time, be overweighted or underweighted to certain industries and sectors relative to its benchmark index. The Fund’s principal investments include the following types of securities and other financial instruments: <ul> <li> Equity securities usually include common stocks, but also may include preferred stocks, convertible securities, and equity interests in trusts, partnerships, and limited liability companies. The Fund also may invest in securities that are tied to the price of stock, including rights and convertible debt securities. </li> <li> Small companies having a market capitalization at the time of purchase that falls within the market capitalization range of companies in the Russell 2000® Index. </li> <li> Growth companies that the Fund believes exhibit faster-than-average gains in earnings and have the potential to continue profit growth at a high level. </li> </ul> The Fund may engage in active and frequent trading of its portfolio securities. The Fund generally will sell a security when the Fund believes the security is less likely to benefit from the current market and economic environment, shows signs of deteriorating fundamentals, or has reached its valuation target, among other reasons. The Fund seeks to remain fully invested in accordance with its investment objective; however, in response to adverse economic, market or other unfavorable conditions, the Fund may invest its assets in a temporary defensive manner. FEES AND EXPENSES This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and certain members of your family invest, or agree to invest in the future, at least $50,000 in the Lord Abbett Family of Funds. More information about these and other discounts is available from your financial professional and in “Sales Charge Reductions and Waivers” on page 24 of the prospectus and “Purchases, Redemptions, Pricing, and Payments to Dealers” on page 8-1 of the statement of additional information (“SAI”). 0.0575 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0500 0.0100 0.0000 0.0000 0.0000 0.0000 0.0000 0.0051 0.0051 0.0051 0.0051 0.0051 0.0051 0.0051 0.0051 0.0035 0.0100 0.0100 0.0010 0.0000 0.0045 0.0060 0.0050 0.0026 0.0026 0.0026 0.0026 0.0026 0.0026 0.0026 0.0026 0.0112 0.0177 0.0177 0.0087 0.0077 0.0122 0.0137 0.0127 ~ http://lordabbett.com/20121127/role/ScheduleShareholderFees20001 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact * row primary compact * ~ ~ http://lordabbett.com/20121127/role/ScheduleOperatingExpenses20002 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact * row primary compact * ~ This amount has been updated from fiscal year amounts to reflect current fees and expenses. You may qualify for sales charge discounts if you and certain members of your family invest, or agree to invest in the future, at least $50,000 in the Lord Abbett Family of Funds. Annual Fund Operating Expenses (Expenses that you pay each year as a percentage of the value of your investment) 50000 Shareholder Fees (Fees paid directly from your investment) Example The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund at the maximum sales charge, if any, for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year, that dividends and distributions are reinvested, and that the Fund’s operating expenses remain the same. The example assumes a deduction of the applicable contingent deferred sales charge (“CDSC”) for the one-year, three-year, and five- year periods for Class B shares and for the one-year period for Class C shares. Class B shares automatically convert to Class A shares after approximately eight years. The expense example for Class B shares for the ten-year period reflects the conversion to Class A shares. The first example assumes that you redeem all of your shares at the end of the periods. Although your actual costs may be higher or lower, based on these assumptions, your costs (including any applicable CDSC) would be as shown below. The second example assumes that you do not redeem and instead keep your shares. 683 911 1156 1860 683 911 1156 1860 680 857 1159 1913 180 557 959 1913 280 557 959 2084 180 557 959 2084 89 278 482 1073 89 278 482 1073 79 246 428 954 79 246 428 954 124 387 670 1477 124 387 670 1477 139 434 750 1646 139 434 750 1646 129 403 697 1534 129 403 697 1534 ~ http://lordabbett.com/20121127/role/ScheduleExpenseExampleTransposed20003 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact * row primary compact * ~ ~ http://lordabbett.com/20121127/role/ScheduleExpenseExampleNoRedemptionTransposed20004 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact * row primary compact * ~ If Shares Are Redeemed If Shares Are Not Redeemed PRINCIPAL RISKS As with any investment in a mutual fund, investing in the Fund involves risk, including the risk that you may receive little or no return on your investment. When you redeem your shares, they may be worth more or less than what you paid for them, which means that you may lose a portion or all of the money you invested in the Fund. The principal risks of investing in the Fund, which could adversely affect its performance, include: <ul> <li> Portfolio Management Risk: If the strategies used and securities selected by the Fund’s portfolio management fail to produce the intended result, the Fund may suffer losses or underperform other funds with the same investment objective or strategies, even in a rising market. </li> <li> Equity Risk: Common stocks and other equity securities, as well as equity-like securities such as convertible bonds, may experience significant volatility. Such securities may fall sharply in response to adverse events affecting overall markets, a particular industry or sector, or an individual company’s financial condition. </li> <li> Small Company Risk: The Fund invests primarily in equity securities of small companies, which typically involve greater investment risks than larger companies. Small companies may have limited management experience or depth, limited ability to generate or borrow capital needed for growth, and limited products or services or operate in markets that have not yet been established. Accordingly, small company securities tend to be more sensitive to changing economic conditions and tend to be more volatile and less liquid than equity securities of larger companies. </li> <li> Growth Investing Risk: The Fund uses a growth investing style, which may be out of favor or may not produce the best results over short or longer time periods. In addition, growth stocks tend to be more volatile than slower-growing value stocks. </li> <li> Foreign Company Risk: The Fund’s investments in foreign (including emerging market) companies and in U.S. companies with economic ties to foreign markets generally involve special risks that can increase the likelihood that the Fund will lose money. For example, as compared with companies organized and operated in the U.S., these companies may be more vulnerable to economic, political, and social instability and subject to less government supervision, inadequate regulatory and accounting standards, and foreign taxes. In addition, the securities of foreign companies also may be subject to inadequate exchange control regulations, higher transaction and other costs, reduced liquidity, and delays in settlement to the extent they are traded on non-U.S. exchanges or markets. Emerging market securities generally are more volatile than other foreign securities, and are subject to greater liquidity, regulatory, and political risks. </li> <li> Industry/Sector Risk: To the extent the Fund overweights a single market sector or industry relative to its benchmark index, it can accumulate relatively large positions in a single issuer, industry, or sector. As a result, the Fund’s performance may be tied more directly to the success or failure of a relatively smaller or less diversified group of portfolio holdings. </li> <li> High Portfolio Turnover Risk: High portfolio turnover (more than 100%) may result in increased brokerage fees or other transaction costs, reduced investment performance, and higher taxes. </li> </ul> An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. For more information on the principal risks of the Fund, please see the “More Information About the Fund – Principal Risks” section in the prospectus. As with any investment in a mutual fund, investing in the Fund involves risk, including the risk that you may receive little or no return on your investment. When you redeem your shares, they may be worth more or less than what you paid for them, which means that you may lose a portion or all of the money you invested in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. INVESTMENT OBJECTIVE The Fund’s investment objective is long-term growth of capital through a diversified and actively managed portfolio consisting of developing growth companies, many of which are traded over the counter. PERFORMANCE The bar chart and table below provide some indication of the risks of investing in the Fund by illustrating the variability of the Fund’s returns. Each assumes reinvestment of dividends and distributions. The Fund’s past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future. Bar Chart (per calendar year) - Class A Shares* -0.2954 0.4006 0.0600 0.1187 0.1245 0.3583 -0.4750 0.4703 0.3654 -0.0166 ~ http://lordabbett.com/20121127/role/ScheduleAnnualTotalReturnsBarChart20005 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact cik0000276914_C000018473Member row primary compact * ~ The bar chart shows changes in the performance of the Fund's ClassA shares from calendar year to calendar year. This chart does not reflect the sales charge applicable to ClassA shares. If the sales charge were reflected, returns would be lower. Performance for the Fund's other share classes will vary due to the different expenses each class bears. Updated performance information is available at www.lordabbett.com or by calling 888-522-2388. Best Quarter 0.2437 2009-06-30 Worst Quarter -0.2860 2008-12-31 The total return for the Fund's Class A shares for the nine-month period from January 1, 2012 to September 30, 2012 was +15.22%. 0.1522 2012-09-30 <table style="WIDTH: 97.24%; MARGIN-LEFT: 0.88%; MARGIN-RIGHT: 0.88%" cellspacing="0"> <tr valign="bottom"> <td style="WIDTH: 51.2%">   </td> <td style="WIDTH: 2.63%">   </td> <td style="WIDTH: 43.06%" align="right">   </td> </tr> <tr valign="bottom"> <td> Best Quarter 2nd Q ‘09 +24.37% </td> <td width="3">   </td> <td align="right"> Worst Quarter 4th Q ’08 -28.60% </td> </tr> </table> <table style="MARGIN-LEFT: 0.33pc; FONT-SIZE: 0.2mm" cellspacing="0" cellpadding="0"> <tr valign="top"> <td style="WIDTH: 5pt">   </td> </tr> <tr valign="top"> <td align="right"> * </td> <td width="3">   </td> <td>   </td> <td width="3">   </td> <td colspan="17"> The total return for the Fund’s Class A shares for the nine-month period from January 1, 2012 to September 30, 2012 was +15.22%. </td> </tr> <tr> <td colspan="99"> </td> </tr> </table> Average Annual Total Returns (for the periods ended December 31, 2011) The table below shows how the Fund’s average annual total returns compare to the returns of a securities index. The Fund’s average annual total returns include applicable sales charges. The after-tax returns of Class A shares included in the table below are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some cases, the return after taxes on distributions and sale of Fund shares may exceed the return before taxes due to a tax benefit resulting from realized losses on a sale of Fund shares at the end of the period that is used to offset other gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax- deferred arrangements such as 401(k) plans or Individual Retirement Accounts (“IRAs”). After-tax returns for other share classes are not shown in the table and will vary from those shown for Class A shares. -0.0732 0.0583 0.0573 -0.0818 0.0497 0.0486 -0.0365 0.0470 0.0462 -0.0684 0.0608 0.0583 -0.0319 0.0640 0.0571 -0.0141 0.0204 -0.0130 0.0746 0.0675 -0.0173 0.0699 0.0627 -0.0191 0.0152 -0.0181 0.0163 -0.0291 0.0209 0.0448 0.0033 2007-09-28 2007-09-28 2007-09-28 2007-09-28 ~ http://lordabbett.com/20121127/role/ScheduleAverageAnnualReturnsTransposed20006 column dei_LegalEntityAxis compact cik0000276914_S000006834Member column rr_ProspectusShareClassAxis compact * column rr_PerformanceMeasureAxis compact * row primary compact * ~ The Fund's average annual total returns include applicable sales charges. The after-tax returns of Class A shares included in the table below are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. The bar chart and table below provide some indication of the risks of investing in the Fund by illustrating the variability of the Fund's returns. The Fund's past performance, before and after taxes, is not necessarily an indication of how the Fund will perform in the future. After-tax returns for other share classes are not shown in the table and will vary from those shown for Class A shares. (reflects no deduction for fees, expenses, or taxes) In some cases, the return after taxes on distributions and sale of Fund shares may exceed the return before taxes due to a tax benefit resulting from realized losses on a sale of Fund shares at the end of the period that is used to offset other gains. This chart does not reflect the sales charge applicable to Class A shares. If the sales charge were reflected, returns would be lower. 888-522-2388 www.lordabbett.com The after-tax returns shown are not relevant to investors who hold their Fund shares through tax- deferred arrangements such as 401(k) plans or Individual Retirement Accounts ("IRAs"). 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 the annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 195.11% of the average value of its portfolio. 1.9511