Summary Prospectus by Investment Company - Form 497K

SUMMARY PROSPECTUS

Lord Abbett Multi-Asset Balanced Opportunity Fund

APRIL 1, 2023

CLASS/TICKER
CLASS A	LABFX	CLASS I	LABYX	CLASS R4	BLASX
CLASS C	BFLAX	CLASS P	LABPX	CLASS R5	BLATX
CLASS F	BLAFX	CLASS R2	BLAQX	CLASS R6	BLAVX
CLASS F3	LOBFX	CLASS R3	BLARX

Before you invest, you may want to review the Fund's prospectus and statement of additional information, which contain more information about the Fund and its risks. You can find the Fund's prospectus, statement of additional information and other information about the Fund at www.lordabbett.com/documentsandliterature. You can also get this information at no cost by calling 888-522-2388 (Option #2) or by sending an email request to [email protected]. The current prospectus and statement of additional information dated April 1, 2023 as may be supplemented from time to time, are incorporated by reference into this summary prospectus.

INVESTMENT OBJECTIVE

The Fund's investment objective is to seek current income and capital growth.

FEES AND EXPENSES

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. 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 $100,000 in the Lord Abbett Family of Funds. More information about these and other discounts is available from your financial intermediary and in "Sales Charge Reductions and Waivers" on page 319 of the prospectus, Appendix A to the prospectus, titled "Intermediary-Specific Sales Charge Reductions and Waivers," and "Purchases, Redemptions, Pricing, and Payments to Dealers" on page 9-1 of Part II of the statement of additional information ("SAI").

Shareholder Fees(1)	(Fees paid directly from your investment)
Class		A	C	F, F3, I, P, R2, R3, R4, R5, and R6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	2.25%	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	None(2)	1.00%(3)	None

Annual Fund Operating Expenses
(Expenses that you pay each year as a percentage of the value of your investment)
Class	A	C	F	F3	I	P
Management Fees	0.10%	0.10%	0.10%	0.10%	0.10%	0.10%
Distribution and Service (12b-1) Fees	0.25%	1.00%	0.10%	None	None	0.45%
Other Expenses	0.16%	0.16%	0.16%	0.08%	0.16%	0.16%
Acquired Fund Fees and Expenses	0.67%	0.67%	0.67%	0.67%	0.67%	0.67%
Total Annual Fund Operating Expenses	1.18%	1.93%	1.03%	0.85%	0.93%	1.38%

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

2

Annual Fund Operating Expenses (continued)
(Expenses that you pay each year as a percentage of the value of your investment)
Class	R2	R3	R4	R5	R6
Management Fees	0.10%	0.10%	0.10%	0.10%	0.10%
Distribution and Service (12b-1) Fees	0.60%	0.50%	0.25%	None	None
Other Expenses	0.16%	0.16%	0.16%	0.16%	0.08%
Acquired Fund Fees and Expenses	0.67%	0.67%	0.67%	0.67%	0.67%
Total Annual Fund Operating Expenses	1.53%	1.43%	1.18%	0.93%	0.85%

(1)	A shareholder transacting in share classes without a front-end sales charge may be required to pay a commission to its financial intermediary. Please contact your financial intermediary for more information about whether such a commission may apply to your transaction.
(2)	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 in which the one-year anniversary of the purchase falls.
(3)	A CDSC of 1.00% may be assessed on Class C shares if they are redeemed before the first anniversary of their purchase.

Example

This 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 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 and that the Fund's operating expenses remain the same. Class C shares automatically convert to Class A shares after eight years. The expense example for Class C shares for the ten-year period reflects the conversion to Class A shares. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Class	If Shares Are Redeemed	If Shares Are Not Redeemed
	1 Year	3 Years	5 Years	10 Years	1 Year	3 Years	5 Years	10 Years
Class A Shares	$	343	$	591	$	859	$	1,625	$	343	$	591	$	859	$	1,625
Class C Shares	$	296	$	606	$	1,042	$	2,059	$	196	$	606	$	1,042	$	2,059
Class F Shares	$	105	$	328	$	569	$	1,259	$	105	$	328	$	569	$	1,259
Class F3 Shares	$	87	$	271	$	471	$	1,049	$	87	$	271	$	471	$	1,049
Class I Shares	$	95	$	296	$	515	$	1,143	$	95	$	296	$	515	$	1,143
Class P Shares	$	140	$	437	$	755	$	1,657	$	140	$	437	$	755	$	1,657
Class R2 Shares	$	156	$	483	$	834	$	1,824	$	156	$	483	$	834	$	1,824
Class R3 Shares	$	146	$	452	$	782	$	1,713	$	146	$	452	$	782	$	1,713
Class R4 Shares	$	120	$	375	$	649	$	1,432	$	120	$	375	$	649	$	1,432
Class R5 Shares	$	95	$	296	$	515	$	1,143	$	95	$	296	$	515	$	1,143
Class R6 Shares	$	87	$	271	$	471	$	1,049	$	87	$	271	$	471	$	1,049

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

3

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 104% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund is a "fund-of-funds" that invests in affiliated mutual funds (the "underlying funds") managed by Lord, Abbett & Co. LLC ("Lord Abbett"). Under normal conditions, through the underlying funds, the Fund indirectly invests in U.S. equity securities across all market capitalization ranges and all investment styles, fixed income securities of various types, and select foreign (including emerging market) securities. The Fund tactically allocates its assets among these asset classes in response to market conditions or to seek to capitalize on investment opportunities. The Fund uses a "blend" strategy to gain investment exposure to both growth and value stocks, or to stocks with characteristics of both.

Equity securities in which an underlying fund may invest include common stocks, preferred stocks, equity interests in trusts (including real estate investment trusts ("REITs") and privately offered trusts), partnerships, joint ventures, limited liability companies and vehicles with similar legal structures, and other instruments with similar characteristics.

Currently, the underlying funds invest in fixed income securities consisting principally of high-yield debt securities, investment grade debt securities, mortgage-related and other asset-backed securities, municipal bonds, U.S. Government securities, convertible securities, bank loans, inflation-linked investments, and cash equivalents. Certain of the underlying funds may invest up to 100% of their assets in fixed income securities that are below investment grade (commonly referred to as "high-yield" or "junk" bonds).

Securities of foreign companies include emerging market companies, American Depositary Receipts ("ADRs"), and other similar depositary receipts, and may be traded on a U.S. or non-U.S. securities exchange and may be denominated in non-U.S. currencies.

In addition to investing in the underlying funds, the Fund may invest directly in any type of derivative as part of its investment strategies or for risk management purposes. Currently, the Fund may invest in derivatives consisting principally of futures, forwards, options, and swaps. To the extent that the Fund invests directly in derivatives, the Fund intends to do so primarily for non-hedging purposes. The market value of the Fund's directly held positions in derivatives, determined at the time of the most recent position established, will not exceed 50% of the Fund's net assets. The Fund currently expects, however, that under normal conditions the market value of such instruments, determined at the time of the most recent position

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

4

established, will not exceed 35% of the Fund's net assets. These percentage limitations exclude Fund assets indirectly invested in derivatives through the underlying funds.

The Fund's portfolio management team tactically allocates the Fund's assets among the underlying funds based on market conditions, interest rate changes, and regulatory developments, among other considerations. The investment team may also consider the risks and return potential presented by environmental, social, and governance ("ESG") factors in investment decisions. The Fund may sell or reallocate its investments among the underlying funds for a variety of reasons, such as to secure gains, limit losses, redeploy assets, increase cash, or satisfy redemption requests, among others. The Fund may deviate from the investment strategy described above for temporary defensive purposes. The Fund may miss certain investment opportunities if defensive strategies are used and thus may not achieve its investment objective.

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 also are the principal risks of investing in the underlying funds. These risks, which could adversely affect the Fund's performance, include:

·Underlying Funds Risk: The assets of the Fund are invested principally in the underlying funds. As a result, the investment performance of the Fund is directly related to the investment performance of the underlying funds in which it invests. The Fund is exposed to the same risks as the underlying funds in direct proportion to the allocation of its assets among the underlying funds. To the extent that the Fund invests a significant portion of its assets in a single underlying fund it may be more susceptible to risks associated with that fund and its investments. It is possible that the holdings of underlying funds may contain securities of the same issuers, thereby increasing the Fund's exposure to such issuers. It also is possible that one underlying fund may be selling a particular security when another is buying it, producing little or no change in exposure but generating transaction costs and/or resulting in realization of gains with no economic benefit. There can be no assurance that the investment objective of any underlying fund will be achieved. In addition, the Fund's shareholders will indirectly bear their proportionate share of the underlying funds' fees and expenses, as well as their proportionate share of the Fund's fees and expenses.

·Affiliated Underlying Funds Risk: The Fund invests principally in underlying funds advised by Lord Abbett, which presents certain conflicts of interest. Generally, Lord Abbett will receive more revenue from investing in the

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

5

underlying funds than it would if it invested in unaffiliated funds. In addition, Lord Abbett is subject to conflicts of interest in allocating portfolio assets among the various underlying funds because the fees payable to Lord Abbett by underlying funds differ.Lord Abbett may have an incentive to select underlying funds that will result in the greatest net management fee revenue to Lord Abbett and its affiliates, even if that results in increased expenses for the Fund. In addition, the Fund's investments in affiliated underlying funds may be beneficial to Lord Abbett in managing the underlying funds, by helping the underlying funds achieve economies of scale or by enhancing cash flows to the underlying funds. In certain circumstances, Lord Abbett would have an incentive to delay or decide against the sale of interests held by the Fund in the underlying funds and may implement Fund changes in a manner intended to minimize the disruptive effects and added costs of those changes to the underlying funds. If the Fund invests in an underlying fund with higher expenses, the Fund's performance would be lower than if the Fund had invested in an underlying fund with comparable performance but lower expenses.

·New Underlying Funds Risk: The Fund may invest in underlying funds that are recently organized. There can be no assurance that a new underlying fund will reach or maintain a sufficient asset size to effectively implement its investment strategy. In addition, a new underlying fund's gross expense ratio may fluctuate during its initial operating period because of the fund's relatively smaller asset size and, until the fund achieves sufficient scale, the Fund may experience proportionally higher expenses than it would experience if it invested in a fund with a larger asset base.

·Portfolio Management Risk: If the strategies used and investments selected by the Fund's portfolio management team 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 favorable market.

·Market Risk: The market values of securities will fluctuate, sometimes sharply and unpredictably, based on overall economic conditions, governmental actions or intervention, market disruptions caused by trade disputes or other factors, political developments, and other factors. Prices of equity securities tend to rise and fall more dramatically than those of debt securities.

·Equity Securities Risk: Equity securities, as well as equity-like securities such as convertible debt securities, 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.

·Industry and Sector Risk: Although the Fund does not employ an industry or sector focus, its exposure to specific industries or sectors will increase from time to time based on the portfolio management team's perception of investment opportunities. If the Fund overweights a single industry or sector relative to its

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

6

benchmark index, the Fund will face an increased risk that the value of its portfolio will decrease because of events disproportionately affecting that industry or sector. Furthermore, investments in particular industries or sectors may be more volatile than the broader market as a whole.

·Large Company Risk: Larger, more established companies may be less able to respond quickly to certain market developments. In addition, larger companies may have slower rates of growth as compared to successful, but less well-established, smaller companies, especially during market cycles corresponding to periods of economic expansion.

·Mid-Sized and Small Company Risk: Investments in mid-sized and small companies may involve greater risks than investments in larger, more established companies. As compared to larger companies, mid-sized and 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 less established markets. Accordingly, securities of mid-sized and small companies tend to be more sensitive to changing economic, market, and industry conditions and tend to be more volatile and less liquid than equity securities of larger companies, especially over the short term. The securities of mid-sized and small companies tend to trade less frequently than those of larger, more established companies, which can adversely affect the pricing of these securities and the ability to sell these securities in the future.

·Blend Style Risk: Growth stocks typically trade at higher multiples of current earnings than other stocks. Growth stocks often are more sensitive to market fluctuations than other securities because their market prices are highly sensitive to future earnings expectations. At times when it appears that these expectations may not be met, prices of growth stocks typically fall. Growth stocks may be more volatile than securities of slower-growing issuers. The prices of value stocks may lag the stock market for long periods of time if the market fails to recognize the company's intrinsic worth. Value investing also is subject to the risk that a company judged to be undervalued may actually be appropriately priced or even overpriced. A portfolio that combines growth and value styles may diversify these risks and lower its volatility, but there is no assurance this strategy will achieve that result.

·Fixed Income Securities Risk: The Fund is subject to the general risks and considerations associated with investing in debt securities, including the risk that issuers will fail to make timely payments of principal or interest or default altogether. Lower-rated securities in which the Fund may invest may be more volatile and may decline more in price in response to negative issuer developments or general economic news than higher rated securities. In addition, as interest rates rise, the Fund's investments typically will lose value.

·High Yield Securities Risk: High yield securities (commonly referred to as "junk" bonds) typically pay a higher yield than investment grade securities, but

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

7

may have greater price fluctuations and have a higher risk of default than investment grade securities. The market for high yield securities may be less liquid due to such factors as interest rate sensitivity, negative perceptions of the junk bond markets generally, and less secondary market liquidity. This may make such securities more difficult to sell at an acceptable price, especially during periods of financial distress, increased market volatility, or significant market decline.

·Loan Risk: Investments in floating or adjustable rate loans are subject to increased credit and liquidity risks. Loan prices also may be adversely affected by supply-demand imbalances caused by conditions in the loan market or related markets. Below investment grade loans, like high-yield debt securities, or junk bonds, usually are more credit sensitive than interest rate sensitive, although the value of these instruments may be affected by interest rate swings in the overall fixed income market. Loans may be subject to structural subordination andmay be subordinated to other obligations of the borrower or its subsidiaries.

·Government Securities Risk: The Fund invests in securities issued or guaranteed by the U.S. Government or its agencies and instrumentalities (such as the Government National Mortgage Association ("Ginnie Mae"), the Federal National Mortgage Association ("Fannie Mae"), or the Federal Home Loan Mortgage Corporation ("Freddie Mac")). Unlike Ginnie Mae securities, securities issued or guaranteed by U.S. Government-related organizations, such as Fannie Mae and Freddie Mac, are not backed by the full faith and credit of the U.S. Government and no assurance can be given that the U.S. Government would provide financial support.

·Municipal Securities Risk: Municipal securities are subject to the same risks affecting fixed income securities in general. In addition, the prices of municipal securities may be adversely affected by legislative or political changes, tax rulings, judicial action, changes in market and economic conditions, and the fiscal condition of the municipal issuer, including an insolvent municipality filing for bankruptcy. The Fund may be more sensitive to these events and conditions if it invests a substantial portion of its assets in the municipal securities of similar projects (such as those relating to education, health care, housing, transportation, and utilities), in particular types of municipal securities (such as general obligation bonds, private activity bonds, and special tax bonds), or in the securities of issuers located within a single state, municipality, territory (such as Puerto Rico), or geographic area. The market for municipal securities generally is less liquid than other securities markets, which may make it more difficult for the Fund to sell its municipal securities. Nongovernmental users of facilities financed by tax-exempt revenue bonds (e.g., companies in the electric utility and health care industries) may have difficulty making payments on their obligations in the event of an economic downturn. This would negatively affect the valuation of municipal securities issued by such facilities.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

8

·Mortgage-Related and Other Asset-Backed Securities Risk: Mortgage-related securities, including commercial mortgage-backed securities ("CMBS") and other privately issued mortgage-related securities, and other asset-backed securities may be particularly sensitive to changes in prevailing interest rates and economic conditions, including delinquencies and defaults.The prices of mortgage-related and other asset-backed securities, depending on their structure and the rate of payments, can be volatile. They are subject to prepayment risk (higher than expected prepayment rates of mortgage obligations due to a fall in market interest rates) and extension risk (lower than expected prepayment rates of mortgage obligations due to a rise in market interest rates). These risks increase the Fund's overall interest rate risk. Some mortgage-related securities receive government or private support, but there is no assurance that such support will remain in place.

·Inflation-Linked Investments Risk: Unlike traditional fixed income securities, the principal and interest payments of inflation-linked investments are adjusted periodically based on the inflation rate. The value of the Fund's inflation-linked investments may be vulnerable to changes in expectations of inflation or interest rates and there is no guarantee that the Fund's use of these instruments will be successful.

·Inverse Floaters Risk: The Fund, through the underlying funds, may invest in inverse floaters. An inverse floater is a type of municipal bond derivative instrument with a floating or variable interest rate that moves in the opposite direction of the interest rate on another security, normally the floating rate note. The value and income of an inverse floater generally is more volatile than the value and income of a fixed rate municipal bond. The value and income of an inverse floater generally fall when interest rates rise. Inverse floaters tend to underperform the market for fixed rate municipal bonds in a rising long-term interest rate environment, but may outperform that market when long-term interest rates decline. Inverse floaters have varying degrees of liquidity, and the market for these securities is relatively volatile. An underlying fund's net cash investment in inverse floaters is significantly less than the value of the underlying municipal bonds. This creates leverage, which increases as the value of the inverse floaters becomes greater in proportion to the value of the underlying municipal bonds.

·Credit Risk: Debt securities are subject to the risk that the issuer or guarantor of a security may not make interest and principal payments as they become due or may default altogether. In addition, if the market perceives a deterioration in the creditworthiness of an issuer, the value and liquidity of securities issued by that issuer may decline. To the extent that the Fund holds below investment grade securities, these risks may be heightened. Insured debt securities have the credit risk of the insurer in addition to the credit risk of the underlying investment being insured.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

9

·Interest Rate Risk: As interest rates rise, prices of bonds (including tax-exempt bonds) generally fall, typically causing the Fund's investments to lose value. Additionally, rising interest rates or lack of market participants may lead to decreased liquidity in fixed income markets. Interest rate changes generally have a more pronounced effect on the market value of fixed-rate instruments, such as corporate bonds, than they have on floating rate instruments, and typically have a greater effect on the price of fixed income securities with longer durations. A wide variety of market factors can cause interest rates to rise, including central bank monetary policy, rising inflation, and changes in general economic conditions. To the extent the Fund invests in floating rate instruments, changes in short-term market interest rates may affect the yield on those investments. If short-term market interest rates fall, the yield on the Fund's shares will also fall. Conversely, when short-term market interest rates rise, because of the lag between changes in such short-term rates and the resetting of the floating rates on the floating rate debt in the Fund's portfolio, the impact of rising rates may be delayed. To the extent the Fund invests in fixed rate instruments, fluctuations in the market price of such investments may not affect interest income derived from those instruments, but may nonetheless affect the Fund's NAV, especially if the instrument has a longer maturity. Substantial increases in interest rates may cause an increase in issuer defaults, as issuers may lack resources to meet higher debt service requirements. Recently, there have been signs of inflationary price movements. As such, fixed income securities markets may experience heightened levels of interest rate volatility and liquidity risk. The United States is currently experiencing a rising interest rate environment, which may increase the Fund's exposure to risks associated with rising interest rates.

·Foreign and Emerging Market Company Risk: Investments in foreign 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, lack of transparency, inadequate regulatory and accounting standards, and foreign taxes. In addition, the securities of foreign companies also may be subject to inadequate exchange control regulations, the imposition of economic sanctions or other government restrictions, higher transaction and other costs, reduced liquidity, and delays in settlement to the extent they are traded on non-U.S. exchanges or markets. Foreign company securities also include American Depositary Receipts ("ADRs"). ADRs may be less liquid than the underlying shares in their primary trading market. Foreign securities also may subject the Fund's investments to changes in currency exchange rates. Emerging market securities generally are more volatile than other foreign securities, and are subject to greater liquidity, regulatory, and political risks. Investments in emerging markets may be considered speculative and generally are riskier than investments in more developed markets because such markets tend to develop

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

10

unevenly and may never fully develop. Emerging markets are more likely to experience hyperinflation and currency devaluations. Securities of emerging market companies may have far lower trading volumes and less liquidity than securities of issuers in developed markets. Companies with economic ties to emerging markets may be susceptible to the same risks as companies organized in emerging markets.

·Foreign Currency Risk: Investments in securities denominated in foreign currencies are subject to the risk that those currencies will decline in value relative to the U.S. dollar, or, in the case of hedged positions, that the U.S. dollar will decline in value relative to the currency being hedged. Foreign currency exchange rates may fluctuate significantly over short periods of time.

·Sovereign Debt Risk: Sovereign debt securities are subject to the risk that the relevant sovereign government or governmental entity may delay or refuse to pay interest or repay principal on its debt, due to, for example, cash flow problems, insufficient foreign currency reserves, political considerations, the size of its debt relative to the economy, or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies. There is no legal process for collecting sovereign debt that is not repaid, nor are there bankruptcy proceedings through which all or part of the unpaid sovereign debt may be collected.

·Convertible Securities Risk: Convertible securities are subject to the risks affecting both equity and fixed income securities, including market, credit, liquidity, and interest rate risk. Convertible securities tend to be more volatile than other fixed income securities, and the markets for convertible securities may be less liquid than markets for common stocks or bonds. To the extent that the Fund invests in convertible securities and the investment value of the convertible security is greater than its conversion value, its price will likely increase when interest rates fall and decrease when interest rates rise. If the conversion value exceeds the investment value, the price of the convertible security will tend to fluctuate directly with the price of the underlying equity security. A significant portion of convertible securities have below investment grade credit ratings and are subject to increased credit and liquidity risks.

·Derivatives Risk: The risks associated with derivatives may be different from and greater than the risks associated with directly investing in securities and other investments. Derivatives may increase the Fund's volatility and reduce its returns. The risks associated with derivatives include, among other things,the following:

·The risk that the value of a derivative may not correlate with the value of the underlying asset, rate, or index in the manner anticipated by the portfolio management team and may be more sensitive to changes in economic or market conditions than anticipated.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

11

·Derivatives may be difficult to value, especially under stressed or unforeseen market conditions.

·The risk that the counterparty may fail to fulfill its contractual obligations under the derivative contract. Central clearing of derivatives is intended to decrease counterparty risk but does not eliminate it.

·The risk that there will not be a liquid secondary trading market for the derivative, or that the Fund will otherwise be unable to sell or otherwise close a derivatives position when desired, exposing the Fund to additional losses.

·Because derivatives generally involve a small initial investment relative to the risk assumed (known as leverage), derivatives can magnify the Fund's losses and increase its volatility.

·The Fund's use of derivatives may affect the amount, timing, and character of distributions, and may cause the Fund to realize more short-term capital gain and ordinary income than if the Fund did not use derivatives.

Derivatives may not perform as expected and the Fund may not realize the intended benefits. Whether the Fund's use of derivatives is successful will depend on, among other things, the portfolio managers' ability to correctly forecast market movements, company and industry valuation levels and trends, changes in foreign exchange and interest rates, and other factors. If the portfolio managers incorrectly forecast these and other factors, the Fund's performance could suffer. In addition, given their complexity, derivatives are subject to the risk that improper or misunderstood documentation may expose the Fund to losses.

·Liquidity/Redemption Risk: The Fund may lose money when selling securities at inopportune times to fulfill shareholder redemption requests. The risk of loss may increase depending on the size and frequency of redemption requests, whether the redemption requests occur in times of overall market turmoil or declining prices, and whether the securities the Fund intends to sell have decreased in value or are illiquid. The Fund may be less able to sell illiquid securities at its desired time or price. It may be more difficult for the Fund to value its investments in illiquid securities than more liquid securities.

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 Funds - Principal Risks" section in the prospectus.

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.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

12

The bar chart shows changes in the performance of the Fund's Class A shares from calendar year to calendar year. This chart does not reflect the sales charge applicable to Class A 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.

Bar Chart (per calendar year) - Class A Shares Best Quarter 2nd Q 2020 +18.41%Worst Quarter 1st Q 2020 -16.88%

The table below shows how the Fund's average annual total returns compare to the returns of securities market indices with investment characteristics similar to those of the Fund. 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-advantaged 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.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

13

Average Annual Total Returns
(for the periods ended December 31, 2022)
Class	1 Year	5 Years	10 Years	Life of Class	Inception Date for Performance
Class A Shares
	Before Taxes	-18.06%	3.46%	5.63%	-
	After Taxes on Distributions	-18.55%	1.30%	3.52%	-
	After Taxes on Distributions and Sale of Fund Shares	-10.59%	2.25%	3.85%	-
Class C Shares(1)	-17.61%	3.15%	5.09%	-
Class F Shares	-16.05%	4.08%	6.04%	-
Class F3 Shares	-15.80%	4.29%	-	5.02%	4/4/2017
Class I Shares	-15.96%	4.19%	6.14%	-
Class P Shares	-16.28%	3.72%	5.67%	-
Class R2 Shares	-16.41%	3.56%	5.51%	-
Class R3 Shares	-16.34%	3.70%	5.63%	-
Class R4 Shares	-16.17%	3.93%	-	4.55%	6/30/2015
Class R5 Shares	-15.93%	4.20%	-	4.81%	6/30/2015
Class R6 Shares	-15.89%	4.26%	-	4.86%	6/30/2015
Index
Russell 1000® Index	-19.13%	9.13%	12.37%	10.35%	6/30/2015
(reflects no deduction for fees, expenses, or taxes)	10.55%	4/4/2017
Morningstar Average
Morningstar Allocation 50-70% Equity Category Average	-13.84%	4.13%	6.01%	4.99%	6/30/2015
(reflects no deduction for sales charges or taxes)	5.25%	4/4/2017

(1)	Class C shares convert to Class A shares eight years after purchase. Class C share performance does not reflect the impact of such conversion to Class A shares.

MANAGEMENT

Investment Adviser. The Fund's investment adviser is Lord Abbett.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

14

Portfolio Managers.

Portfolio Managers/Title	Member of the Portfolio Management Team Since
Giulio Martini, Partner and Director of Strategic Asset Allocation	2015
Robert A. Lee, Partner and Co-Head of Taxable Fixed Income	2016
Jeffrey O. Herzog, Managing Director and Portfolio Manager	2016
Steven F. Rocco, Partner and Co-Head of Taxable Fixed Income	2022

PURCHASE AND SALE OF FUND SHARES

The minimum initial and additional amounts shown below vary depending on the class of shares you buy and the type of account. Certain financial intermediaries may impose different restrictions than those described below. For Class I shares, the minimum investment shown below applies to certain types of institutional investors, but does not apply to registered investment advisers or retirement and benefit plans otherwise eligible to invest in Class I shares. Class P shares are closed to substantially all new investors. See "Choosing a Share Class - Investment Minimums" in the prospectus for more information.

Investment Minimums - Initial/Additional Investments
Class	A(1) and C	F, F3, P, R2, R3, R4, R5, and R6	I
General and IRAs without Invest-A-Matic Investments	Initial: $1,500 Additional: No minimum	N/A	Initial: $1 million Additional: No minimum
Invest-A-Matic Accounts(2)	Initial: $250 Additional: $50	N/A	N/A
IRAs, SIMPLE and SEP Accounts with Payroll Deductions	No minimum	N/A	N/A
Fee-Based Advisory Programs and Retirement and Benefit Plans	No minimum	No minimum	No minimum
(1)There is no investment minimum for Class A shares purchased by investors maintaining an account with a financial intermediary that has entered into an agreement with Lord Abbett Distributor LLC ("Lord Abbett Distributor") to offer Class A shares through a load-waived network or platform, which may or may not charge transaction fees. (2)There is no minimum initial investment for Invest-A-Matic accounts held directly with the Fund, including IRAs.

You may sell (redeem) shares through your securities broker, financial professional or financial intermediary on any business day the Fund calculates its net asset value ("NAV"). If you have direct account access privileges, you may redeem your shares by contacting the Fund in writing at Lord Abbett Funds Service Center, P.O. Box 534489, Pittsburgh, PA 15253-4489 (regular mail) or 500 Ross Street 154-0520, Attention: 534489, Pittsburgh, PA 15262 (overnight mail), by calling 888-522-2388 or by accessing your account online at www.lordabbett.com.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

15

TAX INFORMATION

The Fund's distributions, if any, generally are taxable to you as ordinary income, capital gains or a combination of the two, unless you are a tax-exempt investor or investing through a tax-advantaged arrangement, such as a 401(k) plan or an IRA. Any withdrawals from such a tax-advantaged arrangement may be taxable to you.

PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase Fund shares through a broker-dealer or other financial intermediary (such as a bank), the Fund and the Fund's distributor or its affiliates may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your individual financial professional to recommend the Fund over another investment. Ask your individual financial professional or visit your financial intermediary's website for more information.

SUMMARY - MULTI-ASSET BALANCED OPPORTUNITY FUND

16

NOTES:

Investment Company Act File Number: 811-07988
	00278396	LABS-7SUM (04/23)

Public link

Please use the above public link if you want to share this noodl on another website.