Summary Prospectus by Investment Company (Form 497K)

Maximum Sales Charge (Load) Imposed on Purchases

(as a percentage of offering price)

Maximum Deferred Sales Charge (Load)

(as a percentage of offering price or redemption proceeds, whichever is lower)

Exchange Fee

Management Fees

Distribution and/or Service (12b-1) Fees

Other Expenses:

Transfer Agent

Interest Expense

Other Expenses

Total Other Expenses

Total Annual Fund Operating Expenses

Fee Waiver and/or Expense Reimbursement(c)

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement(d)

Purchases of Class A shares in amounts of $1,000,000 or more, or by certain group retirement plans, may be subject to a 1%, 1-year contingent deferred sales charge, or CDSC, which may be subject to waiver in certain circumstances.

For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after eight years.

The Adviser has contractually agreed to waive its management fees and/or to bear certain expenses of the Fund until January 31, 2027 to the extent necessary to prevent total Fund operating expenses (excluding acquired fund fees and expenses other than the advisory fees of any AB Funds in which the Fund may invest, interest expense, taxes, extraordinary expenses, and brokerage commissions and other transaction costs), on an annualized basis, from exceeding 0.77%, 1.52%, 0.52% and 0.52% of average daily net assets, respectively, for Class A, Class C, Advisor Class and Class Z shares ("expense limitations"). The expense limitations will remain in effect until January 31, 2027 and may only be terminated or changed with the consent of the Fund's Board of Directors. In addition, the agreement will be automatically extended for one-year terms unless the Adviser provides notice of termination to the Fund at least 60 days prior to the end of the period.

If interest expense were excluded, net expenses would be as follows:

After 1 Year

After 3 Years

After 5 Years

After 10 Years

If you did not redeem your shares at the end of the period, your expenses would be decreased by approximately $100.

Market Risk: The value of the Fund's assets will fluctuate as the market or markets in which the Fund invests fluctuate. The value of the Fund's investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events, including public health crises (including the occurrence of a contagious disease or illness), terrorism, war, changing interest rate levels, the imposition of new or additional tariffs, and regional and global conflicts, that affect large portions of the market.

Credit Risk: An issuer or guarantor of a fixed-income security, or the counterparty to a derivatives or other contract, may be unable or unwilling to make timely payments of interest or principal, or to otherwise honor its obligations. The issuer or guarantor may default, causing a loss of the full principal amount of a security and accrued interest. The degree of risk for a particular security may be reflected in its credit rating. There is the possibility that the credit rating of a fixed-income security may be downgraded after purchase, which may adversely affect the value of the security.

Below Investment Grade Securities Risk: Investments in fixed-income securities with lower ratings (commonly known as "junk bonds") are subject to higher probability that an issuer will default or fail to meet its payment obligations. These securities may be subject to greater price volatility due to such factors as specific corporate developments and negative perceptions of the junk bond market generally and may be more difficult to trade than other types of securities.

Interest Rate Risk: Changes in interest rates will affect the value of investments in fixed-income securities. When interest rates rise, the value of existing investments in fixed-income securities tends to fall and this decrease in value may not be offset by higher income from new investments. Interest rate risk is generally greater for fixed-income securities with longer maturities or durations. Changing interest rates may have unpredictable effects on the markets, may result in heightened market volatility and may detract from Fund performance. In addition, changes in monetary policy may exacerbate the risks associated with changing interest rates.

Duration Risk: Duration is a measure that relates the expected price volatility of a fixed-income security to changes in interest rates. The duration of a fixed-income security may be shorter than or equal to the full maturity of a fixed-income security. Fixed-income securities with longer durations have more risk and will decrease in price as interest rates rise.

Inflation Risk: This is the risk that the value of assets or income from investments will be less in the future as inflation decreases the value of money. As inflation increases, the value of the Fund's assets can decline, as can the value of the Fund's distributions. This risk is significantly greater for fixed-income securities with longer maturities.

Foreign (Non-U.S.) Risk: Investments in securities of non-U.S. issuers may involve more risk than those of U.S. issuers. These securities may fluctuate more widely in price and may be more difficult to trade due to adverse market, economic, political, regulatory or other factors.

Emerging Market Risk: Investments in emerging market countries may have more risks than investments in other foreign countries because the markets are less developed, less liquid and are subject to increased potential for market manipulation and increased economic, political, regulatory or other uncertainties.

Currency Risk: Fluctuations in currency exchange rates may negatively affect the value of the Fund's investments or reduce its returns.

Illiquid Investments Risk: Illiquid investments risk exists when certain investments become difficult to purchase or sell. Difficulty in selling such investments may result in sales at disadvantageous prices affecting the value of your investment in the Fund. Causes of illiquid investments risk may include low trading volumes, large positions and heavy redemptions of Fund shares. Illiquid investments risk may be higher in a rising interest rate environment, when the value and liquidity of fixed-income securities generally decline.

Leverage Risk: To the extent the Fund uses leveraging techniques, its net asset value, or NAV, may be more volatile because leverage tends to exaggerate the effect of changes in interest rates and any increase or decrease in the value of the Fund's investments.

Derivatives Risk: Derivatives may be difficult to price or unwind and leveraged so that small changes may produce disproportionate losses for the Fund. A short position in a derivative instrument involves the risk of a theoretically unlimited increase in the value of the underlying asset, reference rate or index, which could cause the Fund to suffer a potentially unlimited loss. Derivatives, especially over-the-counter derivatives, are also subject to counterparty risk, which is the risk that the counterparty (the party on the other side of the transaction) on a derivative transaction will be unable or unwilling to honor its contractual obligations to the Fund.

Active Trading Risk: The Fund expects to engage in active and frequent trading of its portfolio securities and its portfolio turnover rate may greatly exceed 100%. A higher rate of portfolio turnover increases transaction costs, which may negatively affect the Fund's return. In addition, a high rate of portfolio turnover may result in substantial short-term gains, which may have adverse tax consequences for Fund shareholders.

Management Risk: The Fund is subject to management risk because it is an actively-managed investment fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions, but there is no guarantee that its techniques will produce the intended results. Some of these techniques may incorporate, or rely upon, quantitative models, but there is no guarantee that these models will generate accurate forecasts, reduce risk or otherwise perform as expected.

how the Fund's performance changed from year to year over ten years; and

how the Fund's average annual returns for one, five and ten years compare to those of a broad-based securities market index.

Bloomberg U.S. Aggregate Bond Index

(reflects no deduction for fees, expenses, or taxes)

Performance information for Class A and Class C shares prior to April 22, 2016 and for Class Z shares prior to November 20, 2019 (Class Z inception date) reflects the performance of the Fund's Advisor Class shares adjusted to reflect the expense differences between these Classes of shares.

After-tax returns:

Are shown for Advisor Class shares only and will vary for the other Classes of shares because these Classes have different expense ratios;

Are an estimate, which is based on the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and

Are not relevant to investors who hold fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

Mr. Distenfeld is expected to retire from the Adviser effective December 31, 2026.

$50

If initial minimum investment is

less than $2,500, then $200

monthly until account balance

reaches $2,500