Alger Mid Cap Growth Fund

Summary Prospectus

March 1, 2020	Class	Ticker Symbol
	Z	AMCZX

Optional Internet Availability of Alger Shareholder Reports

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from the Fund or from your financial intermediary. 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 link 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 by signing up for paperless delivery at www.icsdelivery.com/alger. If you own these shares through a financial intermediary, contact your financial intermediary.

You may elect to receive all future reports in paper free of charge. You can inform the Fund that you wish to continue receiving paper copies of your shareholder reports by contacting us at 1-866-345-5954 or fundreports.com. If you own these shares through a financial intermediary, contact your financial intermediary to elect to continue to receive paper copies of your shareholder reports. Your election to receive reports in paper will apply to all funds held with the Alger Fund Complex or your financial intermediary.

Before you invest, you may want to review the Fund’s Prospectus, which contains more information about the Fund and its risks. You can find the Fund’s Prospectus, reports to shareholders, and other information about the Fund online at www.alger.com. You can also get this information at no cost by calling (800) 992-3863 or by sending an e-mail request to summaryprospectus@alger.com. The Fund’s Prospectus and Statement of Additional Information, both dated March 1, 2020, are incorporated by reference to this Summary Prospectus, and may be obtained at no cost in the same manner as described above.

Investment Objective

Alger Mid Cap Growth Fund seeks long-term capital appreciation.

Fund Fees and Expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. Investors may also incur brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows.

	Alger Mid Cap Growth Fund
Class	Z
Shareholder Fees (fees paid directly from your investment)	None
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Advisory Fees	.76%
Distribution and/or Service (12b-1) Fees	None
Other Expenses	.27%
Total Annual Fund Operating Expenses*	1.03%

* Fred Alger Management, LLC has contractually agreed to waive fees or to reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, borrowing costs, interest, taxes, brokerage and extraordinary expenses) through February 28, 2021, to the extent necessary to limit the total annual fund operating expenses of the Class Z Shares to 1.05% of the class’s average daily net assets. This expense reimbursement may only be amended or terminated prior to its expiration date by agreement between Fred Alger Management, LLC and the Fund’s Board of Trustees, and will terminate automatically in the event of termination of the Investment Advisory Agreement.

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 for the time periods indicated, that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. The one-year example and the first year of the three-, five- and ten-year examples are based on net operating expenses, which reflect the contractual expense limitation agreed to by

Inspired by Change, Driven by Growth.

Alger Mid Cap Growth Fund 2/4

Summary Prospectus

March 1, 2020

Fred Alger Management, LLC. Although your actual costs may be higher or lower, based on these assumptions you would pay the following expenses whether or not you redeemed your shares at the end of each period:

	1 Year	3 Years	5 Years	10 Years
Class Z	$105	$328	$569	$1,259

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 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 182.97% of the average value of its portfolio.

Principal Investment Strategy

Fred Alger Management, LLC believes companies undergoing Positive Dynamic Change offer the best investment opportunities. Positive Dynamic Change refers to companies realizing High Unit Volume Growth or companies undergoing Positive Lifecycle Change. High Unit Volume Growth companies are traditional growth companies experiencing, for example, rapidly growing demand or market dominance. Positive Lifecycle Change companies are, for example, companies benefitting from new regulations, a new product innovation or new management.

The Fund focuses on mid-sized companies that Fred Alger Management, LLC believes demonstrate promising growth potential. Under normal circumstances, the Fund invests at least 80% of its net assets in equity securities of companies that, at the time of purchase of the securities, have total market capitalization within the range of companies included in the Russell Midcap Growth Index or the S&P MidCap 400 Index, as reported by the indexes as of the most recent quarter-end. Both indexes are designed to track the performance of medium-capitalization stocks. At December 31, 2019, the market capitalization of the companies in these indexes ranged from $1.10 billion to $78.61 billion. Because of the Fund’s long-term approach to investing, it could have a significant portion of its assets invested in securities of issuers that have appreciated beyond the market capitalization thresholds noted. Equity securities include common or preferred stocks that are listed on U.S. or foreign exchanges.

The Fund may invest a significant portion of its assets in securities of companies conducting business within a single sector, including the information technology, healthcare, consumer discretionary, and industrials sectors.

The Fund’s portfolio manager(s) may sell a stock when it reaches a target price, it fails to perform as expected, or other opportunities appear more attractive. As a result, the Fund may engage in active trading of portfolio securities.

The Fund can invest in foreign securities.

Principal Risks

An investment in the Fund involves risks. The Fund’s share price may go down, which means you could lose money. 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.

Investment Risk – An investment in the Fund is subject to investment risk, including the possible loss of the entire principal amount that you invest.

Market Risk – Your investment in Fund shares represents an indirect investment in the securities owned by the Fund. The value of these securities, like other investments, may move up or down, sometimes rapidly and unpredictably. Your Fund shares at any point in time may be worth less than what you invested, even after taking into account the reinvestment of Fund dividends and distributions.

Equity Securities Risk – As with any fund that invests in stocks, your investment will fluctuate in value, and the loss of your investment is a risk of investing. The Fund’s price per share will fluctuate due to changes in the market prices of its investments. Also, the Fund’s investments may not grow as fast as the rate of inflation and stocks tend to be more volatile than some other investments you could make, such as bonds.

Growth Stocks Risk – Prices of growth stocks tend to be higher in relation to their companies’ earnings and may be more sensitive to market, political and economic developments than other stocks, making their prices more volatile. An investment in the Fund may be better suited to investors who seek long-term capital growth and can tolerate fluctuations in their investment’s value.

Alger Mid Cap Growth Fund 3/4

Summary Prospectus

March 1, 2020

Mid Cap Securities Risk – There may be greater risk in investing in medium-capitalization companies rather than larger, more established companies due to such factors as inexperienced management and limited product lines or financial resources. It may also be difficult or impossible to liquidate a security position at a time and price acceptable to the Fund because of the potentially less frequent trading of stocks of smaller market capitalization.

Sector Risk – The Fund may have a significant portion of its assets invested in securities of companies conducting business within a single sector. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than a fund that has a more diversified portfolio. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

Technology Companies Risk – The Fund may have a significant portion of its assets invested in securities of technology companies. Many technology companies’ securities have historically been more volatile than other securities, especially over the short term. Technology companies may also face increased competition, government regulation, and risk of obsolescence due to progress in technological developments.

Healthcare Companies Risk – The Fund may have a significant portion of its assets invested in securities of healthcare companies. At times, the performance of healthcare companies will lag the performance of other industries or the broader market as a whole, and the performance of such companies may be more volatile. Healthcare companies may also be significantly affected by intense competition, aggressive pricing, government regulation, technological innovations, product obsolescence, patent considerations, product compatibility and consumer preferences.

Foreign Securities Risk – The Fund’s performance will be influenced by political, social and economic factors affecting investments in foreign companies. Special risks associated with investments in foreign companies include exposure to currency fluctuations, less liquidity, less developed or less efficient trading markets, lack of comprehensive company information, political instability and differing audit and legal standards.

Portfolio Turnover (Active Trading) Risk – Because the Fund may engage in active trading of portfolio securities, it may incur increased transaction costs and brokerage commissions, both of which can lower the actual return on an investment. Active trading may also increase short-term gains and losses, which may affect the taxes a shareholder has to pay.

Performance

The following bar chart and the table beneath it provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns for the indicated periods compare with those of an appropriate benchmark of market performance. The Fund’s past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. Updated performance information is available on the Fund’s website www.alger.com.

Annual Total Return for Class Z Sharesas of December 31 (%)

Best Quarter: Q1 2019 20.50% Worst Quarter: Q4 2018 -22.09%

Alger Mid Cap Growth Fund 4/4

Summary Prospectus

March 1, 2020

Average Annual Total Return as of December 31, 2019

	1 Year	Since Inception
Class Z (Inception 5/28/15)
Return Before Taxes	30.27%	8.21%
Return After Taxes on Distributions	27.88%	7.39%
Return After Taxes on Distributions and Sale of Shares	19.58%	6.36%
Russell Midcap Growth Index (reflects no deductions for fees, expenses or taxes)	35.47%	11.16%

In the foregoing table, after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown may not be relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. A “Return After Taxes on Distributions and Sale of Fund Shares” may sometimes be higher than the other two return figures; this happens when there is a capital loss on redemptions, giving rise to a tax benefit to the shareholder.

Management

Investment Manager	Portfolio Managers Jointly and Primarily Responsible for Day-to-Day Management of the Fund’s Portfolio
Fred Alger Management, LLC	Dan C. Chung, CFA Chief Executive Officer, Chief Investment Officer and Portfolio Manager Since January 2018
	Teresa McRoberts Senior Vice President Since February 2013, Senior Analyst and Portfolio Manager Since February 2015

Although the Fund is co-managed, one of the portfolio managers may be primarily responsible for implementation of the day to day investment decisions. This may occur to ensure that the Fund’s investment decisions are consistently and promptly implemented.

Shareholder Information

Purchasing and Redeeming Fund Shares

The Fund’s Class Z Shares are generally subject to a minimum initial investment of $500,000, which may be waived for group employer-sponsored 401(k) plans, 457 plans, employer sponsored 403(b) plans, profit-sharing and money purchase pension plans, defined benefit plans, retiree health benefit plans and non-qualified deferred compensation plans. The waiver is available only for retirement plans that hold omnibus positions, or for aggregate plan participant positions, for each Fund made available for the plan. The waiver is generally not available to non-retirement accounts, traditional and Roth Individual Retirement Accounts, Coverdell Education Savings Accounts, SEPs, SARSEPs, SIMPLE IRAs, individual 401(k) plans or individual 403(b) plans.

Investors may purchase or redeem Fund shares on any business day through a financial intermediary.

Tax Information

The Fund’s distributions may be taxable as ordinary income or capital gains. The Fund is actively managed, and as a result, investors may receive capital gains distributions annually.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and/or its Manager or Distributor 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 intermediary and your financial advisor to recommend the Fund over another investment. Ask your financial advisor or visit your financial intermediary’s website for more information.

Mid CapZ 3120

Fred Alger & Company, LLC 360 Park Avenue South, New York, NY 10010 / 800.992.3863 / www.alger.com