What is the Fund’s investment objective?

Delaware U.S. Growth Fund seeks long-term capital appreciation by investing in equity securities of companies we believe have the potential for sustainable free cash flow growth.

What are the Fund’s fees and expenses?

The table below 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 your family invest, or agree to invest in the future, at least $50,000 in Delaware Funds® by Macquarie. More information about these and other discounts is available from your financial intermediary, in the Fund’s Prospectus under the section entitled “About your account,” and in the Fund’s statement of additional information (SAI) under the section entitled “Purchasing Shares.”

Shareholder fees (fees paid directly from your investment)

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

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. In addition, the example shows expenses for Class C shares, assuming those shares were not redeemed at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the Manager’s expense waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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 54% of the average value of its portfolio.

What are the Fund’s principal investment strategies?

Under normal circumstances, the Fund will invest at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in US investments (80% policy). The Fund invests primarily in common stocks of companies that its portfolio managers believe have long-term capital appreciation potential and are expected to grow faster than the US economy. Using a bottom-up approach, the portfolio managers seek to select securities they believe have large end-market potential, dominant business models, and strong free cash flow generation that are attractively priced compared to the intrinsic value of the securities. The portfolio managers also consider a company’s operational efficiencies, management’s plans for capital allocation, and the company’s shareholder orientation. All of these factors give the portfolio managers insight into the outlook for a company, helping identify companies poised for sustainable free cash flow growth. The portfolio managers believe that sustainable free cash flow growth, if it occurs, may result in price appreciation for the company’s stock. The portfolio managers may sell a security if they no longer believe that the security is likely to contribute to meeting the investment objective of the Fund or if there are other opportunities that appear more attractive.

The Fund’s 80% policy is nonfundamental and may be changed without shareholder approval. Fund shareholders would be given at least 60 days’ notice prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund’s portfolio. An investment in the Fund may not be appropriate for all investors. The Fund’s principal risks include:

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Liquidity risk — The possibility that investments cannot be readily sold within seven calendar days at approximately the price at which a fund has valued them.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability, changes in currency exchange rates, inefficient markets and higher transaction costs, foreign economic conditions, the imposition of economic or trade sanctions, or inadequate or different regulatory and accounting standards.

IBOR risk — The risk that changes related to the use of the London Interbank Offered Rate (LIBOR) or similar interbank offered rates (“IBORs,” such as the Euro Overnight Index Average (EONIA)) could have adverse impacts on financial instruments that reference LIBOR or a similar rate. While some instruments may contemplate a scenario where LIBOR or a similar rate is no longer available by providing for an alternative rate setting methodology, not all instruments have such fallback provisions and the effectiveness of replacement rates is uncertain. The abandonment of LIBOR and similar rates could affect the value and liquidity of instruments that reference such rates, especially those that do not have fallback provisions. The use of alternative reference rate products may impact investment strategy performance.

Active management and selection risk — The risk that the securities selected by a fund’s management will underperform the markets, the relevant indices, or the securities selected by other funds with similar investment objectives and investment strategies. The securities and sectors selected may vary from the securities and sectors included in the relevant index.

The Manager is an indirect wholly owned subsidiary of Macquarie Group Limited (MGL). Other than Macquarie Bank Limited (MBL), a subsidiary of MGL and an affiliate of the Manager, none of the entities noted are authorized deposit-taking institutions for the purposes of the Banking Act 1959 (Commonwealth of Australia). The obligations of these entities do not represent deposits or other liabilities of MBL. MBL does not guarantee or otherwise provide assurance in respect of the obligations of these entities, unless noted otherwise. The Fund is governed by US laws and regulations.

How has Delaware U.S. Growth Fund performed?

The bar chart and table below 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 total returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure 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. The returns reflect any expense caps in effect during these periods. The returns would be lower without the expense caps. You may obtain the Fund’s most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawarefunds.com/performance.

Calendar year-by-year total return (Class A)

During the periods illustrated in this bar chart, Class A’s highest quarterly return was 29.79% for the quarter ended June 30, 2020, and its lowest quarterly return was -14.19% for the quarter ended Dec. 31, 2018. The maximum Class A sales charge of 5.75%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual total returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2020

Frank Russell Company is the source and owner of the trademarks, service marks, and copyrights related to the Russell Indexes. Russell® is a trademark of Frank Russell Company.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor’s individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-advantaged investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Who manages the Fund?

Investment manager

Delaware Management Company, a series of Macquarie Investment Management Business Trust (a Delaware statutory trust)

Sub-advisor

Jackson Square Partners, LLC (JSP)

Purchase and redemption of Fund shares

You may purchase or redeem shares of the Fund on any day that the New York Stock Exchange (NYSE) is open for business (Business Day). Shares may be purchased or redeemed: through your financial intermediary; through the Fund’s website at delawarefunds.com/account-access; by calling 800 523-1918; by regular mail (c/o Delaware Funds® by Macquarie, P.O. Box 9876, Providence, RI 02940-8076); by overnight courier service (c/o Delaware Funds by Macquarie Service Center, 4400 Computer Drive, Westborough, MA 01581-1722); or by wire.

For Class A and Class C shares, the minimum initial investment is generally $1,000 and subsequent investments can be made for as little as $100. The minimum initial investment for IRAs, Uniform
Gifts/Transfers to Minors Act accounts, direct deposit purchase plans, and automatic investment plans is $250 and through Coverdell Education Savings Accounts is $500, and subsequent investments in these accounts can be made for as little as $25. For Class R, Institutional Class, and Class R6 shares (except those shares purchased through an automatic investment plan), there is no minimum initial purchase requirement, but certain eligibility requirements must be met. The eligibility requirements are described in this Prospectus under “Choosing a share class” and on the Fund’s website. We may reduce or waive the minimums or eligibility requirements in certain cases.

Please refer to the Fund’s prospectus and statement of additional information for more details regarding the purchase and sale of Fund shares.

Tax information

The Fund’s distributions generally are taxable to you as ordinary income, capital gains, or some combination of both, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an IRA, in which case your distributions may be taxed as ordinary income when withdrawn from the tax-advantaged account.

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), 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 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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