SUMMARY PROSPECTUS    October 31, 2019

AB Concentrated Growth Fund

Ticker: Class A–WPASX; Class C–WPCSX; Class R–WPRSX; Class K–WPSKX; Class I–WPSIX;

Advisor Class–WPSGX; Class Z–WPSZX

Before you invest, you may want to review the Fund’s Prospectus, which contains more information about the Fund and its risks. The Fund’s Prospectus and Statement of Additional Information (“SAI”), both dated October 31, 2019, are incorporated by reference into this Summary Prospectus. For free paper or electronic copies of the Fund’s Prospectus, reports to shareholders and other information about the Fund, go to www.abfunds.com/go/prospectus, email a request to prorequest@alliancebernstein.com, call (800) 227-4618, or ask any financial advisor, bank, or broker-dealer who offers shares of the Fund.

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Beginning January 1, 2021, as permitted by new regulations adopted by the Securities and Exchange Commission, the Fund’s annual and semi-annual shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website address to access the report.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from the Fund electronically at any time by contacting your financial intermediary (such as a broker-dealer or bank) or, if you are a direct investor, by calling the Fund at (800) 221-5672.

You may elect to receive all future reports in paper form free of charge. If you invest through a financial intermediary, you can contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports; if you invest directly with the Fund, you can call the Fund at (800) 221-5672. Your election to receive reports in paper form will apply to all funds held in your account with your financial intermediary or, if you invest directly, to all AB Mutual Funds you hold.

INVESTMENT OBJECTIVE

The Fund’s investment objective is long-term growth of capital.

FEES AND EXPENSES OF THE FUND

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 reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds. More information about these and other discounts is available from your financial intermediary and in Investing in the Funds—Sales Charge Reduction Programs for Class A Shares on page 65 of the Fund’s Prospectus, in Appendix B—Financial Intermediary Waivers of the Fund’s Prospectus and in Purchase of Shares—Sales Charge Reduction Programs for Class A Shares on page 130 of the Fund’s SAI.

You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or the examples below.

Shareholder Fees (fees paid directly from your investment)

	Class A Shares	Class C Shares	Advisor Class Shares	Class R, K, I and Z Shares
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	4.25%	None	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	None(a)	1.00%(b)	None	None
Exchange Fee	None	None	None	None

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Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

	Class A			Class C			Advisor Class			Class R			Class K		Class I		Class Z
Management Fees		.80%			.80%			.80%			.80%			.80%		.80%		.80%
Distribution and/or Service (12b-1) Fees		.25%			1.00%			None			.50%			.25%		None		None
Other Expenses:
Transfer Agent		.05%			.05%			.05%			.06%			.05%		.02%		.02%
Other Expenses		.09%			.09%			.09%			.08%			.10%		.10%		.10%
Total Other Expenses		.14%			.14%			.14%			.14%			.15%		.12%		.12%
Acquired Fund Fees and Expenses(c)		.00%			.00%			.00%			.00%			.00%		.00%		.00%
Total Annual Fund Operating Expenses		1.19%			1.94%			.94%			1.44%			1.20%		.92%		.92%
Fee Waiver and/or Expense Reimbursement(d)		(.00)%	(c)		(.00)%	(c)		(.00)%	(c)		(.00)%	(c)		(.01)%		(.01)%		(.01)%
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		1.19%			1.94%			.94%			1.44%			1.19%		.91%		.91%

(a) 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.

(b) For Class C shares, the CDSC is 0% after the first year. Class C shares automatically convert to Class A shares after ten years.

(c) Amount is less than .005%.

(d) In connection with the Fund’s investments in AB Government Money Market Portfolio (the “Money Market Portfolio”) (except for the investment of any cash collateral from securities lending), the Adviser has contractually agreed to waive its management fee from the Fund and/or reimburse other expenses of the Fund in an amount equal to the Fund’s pro rata share of the Money Market Portfolio’s effective management fee, as included in “Acquired Fund Fees and Expenses”.

Examples

The Examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Examples assume 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 Examples also assume that your investment has a 5% return each year, that the Fund’s operating expenses stay the same and that any fee waiver remains in effect for only the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	Class A		Class C			Advisor Class		Class R		Class K		Class I		Class Z
After 1 Year	$	541	$	297	*	$	96	$	147	$	121	$	93	$	93
After 3 Years	$	787	$	609		$	300	$	456	$	380	$	292	$	292
After 5 Years	$	1,052	$	1,047		$	520	$	787	$	659	$	508	$	508
After 10 Years	$	1,807	$	2,264		$	1,155	$	1,724	$	1,454	$	1,130	$	1,130

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

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys or 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 transaction costs, which are not reflected in the Annual Fund Operating Expenses or in the Examples, affect the Fund’s performance. During the most recent fiscal period, the Fund’s portfolio turnover rate was 30% of the average value of its portfolio.

PRINCIPAL STRATEGIES

The Adviser seeks to achieve the Fund’s investment objective of long-term growth of capital by investing primarily in common stocks of listed U.S. companies. The Adviser employs an appraisal method that attempts to measure each prospective company’s quality and growth rate by numerous factors. Such factors include: a company’s record and projections of profit and earnings growth, accuracy and availability of information with respect to the company, success and experience of management, accessibility of management to the Fund’s Adviser, product lines and competitive position both in the United States and abroad, lack of cyclicality, large market capitalization and liquidity of the company’s securities. The Adviser compares these results to the general stock markets to determine the relative attractiveness of each company at a given time. The Adviser weighs economic, political and market factors in making investment decisions; this appraisal technique attempts to measure each investment candidate not only against other stocks of the same industry group, but also against a broad spectrum of investments. While the Fund primarily invests in companies that have market capitalizations of $5 billion or more, it may invest in companies that have market capitalizations of $3 billion to $5 billion.

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The Fund invests in a relatively small number of individual stocks. The Fund is considered to be “non-diversified”, which means that the securities laws do not limit the percentage of its assets that it may invest in any one company (subject to certain limitations under the Internal Revenue Code of 1986, as amended).

PRINCIPAL RISKS

• Market Risk: The value of the Fund’s assets will fluctuate as the equity markets fluctuate. The value of the Fund’s investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events that affect large portions of the market.

• Focused Portfolio Risk: Investments in a limited number of companies may have more risk because changes in the value of a single security may have a more significant effect, either negative or positive, on the Fund’s net asset value, or NAV.

• Sector Risk: The Fund may have more risk because it may invest to a significant extent in one or more particular market sectors, such as the information technology or health care sector. To the extent it does so, market or economic factors affecting the relevant sector(s) could have a major effect on the value of the Fund’s investments.

• Capitalization Risk: Investments in mid-capitalization companies may be more volatile and less liquid than investments in large-capitalization companies.

• Non-diversification Risk: The Fund may have more risk because it is “non-diversified”, meaning that it can invest more of its assets in a smaller number of issuers. Accordingly, changes in the value of a single security may have a more significant effect, either negative or positive, on the Fund’s NAV.

• 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 for the Fund, but there is no guarantee that its techniques will produce the intended results.

As with all investments, you may lose money by investing in the Fund.

BAR CHART AND PERFORMANCE INFORMATION

The bar chart and performance information provide an indication of the historical risk of an investment in the Fund by showing:

• 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.

You may obtain updated performance information on the Fund’s website at www.abfunds.com (click on “Investments—Mutual Funds”).

The Fund’s past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.

The information shown below reflects the historical performance of the W.P. Stewart & Co. Growth Fund and that fund’s predecessor (together the “Predecessor Fund”) prior to the reorganization of the Predecessor Fund into Advisor Class shares of the Fund on February 28, 2014. The Predecessor Fund and the Fund have substantially similar investment strategies and the same portfolio management team.

Bar Chart

The annual returns in the bar chart are for the Predecessor Fund’s shares for periods prior to its reorganization into Advisor Class shares of the Fund. Through September 30, 2019, the year-to-date unannualized return for Advisor Class shares was 28.27%.

During the period shown in the bar chart, the Fund’s:

Best Quarter was up 17.10%, 1st quarter, 2012; and Worst Quarter was down -12.73%, 2nd quarter, 2010.

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Performance Table

Average Annual Total Returns

(For the periods ended December 31, 2018)

		1 Year		5 Years		10 Years
Class  A*,**	Return Before Taxes		-3.08%		7.35%		12.85%
	Return After Taxes on Distributions		-4.73%		6.36%		12.33%
	Return After Taxes on Distributions and Sale of Fund Shares		-0.51%		5.68%		10.75%
Class C*	Return Before Taxes		-0.49%		7.48%		12.50%
Advisor Class	Return Before Taxes		1.48%		8.55%		13.63%
Class R*	Return Before Taxes		0.94%		8.01%		13.06%
Class K*	Return Before Taxes		1.23%		8.29%		13.35%
Class I*	Return Before Taxes		1.51%		8.58%		13.64%
Class Z*	Return Before Taxes		1.48%		8.57%		13.64%
S&P 500® Index (reflects no deduction for fees, expenses, or taxes)			-4.38%		8.49%		13.12%

* Inception date for Class A, Class C, Class R, Class K, Class I and Class Z shares: 2/28/14. Performance information for periods prior to the inception of Class A, Class C, Class R, Class K, Class I and Class Z shares is the performance of the Fund’s Advisor Class shares adjusted to reflect the respective expense ratios of the Class A, Class C, Class R, Class K, Class I and Class Z shares.

** After-tax returns:

– Are shown for Class A 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.

INVESTMENT ADVISER

AllianceBernstein L.P. is the investment adviser for the Fund.

PORTFOLIO MANAGER

The following table lists the person responsible for day-to-day management of the Fund’s portfolio:

Employee	Length of Service	Title
James Tierney	Since 2013	Senior Vice President of the Adviser

PURCHASE AND SALE OF FUND SHARES

Purchase Minimums

The following table describes the initial and subsequent minimum purchase amounts for each class of shares, which are subject to waiver in certain circumstances.

	Initial	Subsequent
Class A/Class C shares, including traditional IRAs and Roth IRAs	$2,500	$50
Automatic Investment Program	None	$50 If initial minimum investment is less than $2,500, then $200 monthly until account balance reaches $2,500
Advisor Class shares (only available to fee-based programs or through other limited arrangements and certain commission-based brokerage arrangements)	None	None
Class A, Class R, Class K, Class I and Class Z shares are available at NAV, without an initial sales charge, to 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit-sharing and money purchase pension plans, defined benefit plans, and non-qualified deferred compensation plans and, for Class Z shares, to persons participating in certain fee-based programs sponsored by a financial intermediary, where in each case plan level or omnibus accounts are held on the books of the Fund.	None	None

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You may sell (redeem) your shares each day the New York Stock Exchange is open. You may sell your shares through your financial intermediary or by mail (AllianceBernstein Investor Services, Inc., P.O. Box 786003, San Antonio, TX 78278-6003) or telephone ((800) 221-5672).

TAX INFORMATION

The Fund may pay income dividends or make capital gains distributions, which may be subject to federal income taxes and taxable as ordinary income or capital gains, and may also be subject to state and local taxes.

PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank or a group retirement plan), the Fund and its related companies 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 salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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