Transamerica Mid Cap Growth

Summary Prospectus March 1, 2026

Class R4 (TMIFX)

Class R (TMIRX)

Class I3 (TMITX)

Thank you for being a valued Transamerica shareholder. This Summary Prospectus will provide you with updated information about your investment in the fund.

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, including the fund’s statement of additional information online at https://www.transamerica.com/financial-pro/investments/prospectus. You can also get this information at no cost by calling 1-888-233-4339 or by sending an e-mail request to orders@mysummaryprospectus.com, or from your financial professional. The fund’s prospectus and statement of additional information, both dated March 1, 2026, as supplemented from time to time, are incorporated by reference into this summary prospectus.

Investment Objective: Seeks long term capital appreciation.

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.

Shareholder Fees (fees paid directly from your investment)

Class:	R4	R	I3
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	None	None	None
Maximum deferred sales charge (load) (as a percentage of purchase price or redemption proceeds, whichever is lower)	None	None	None

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

Class:	R4	R	I3
Management fees	0.71%	0.71%	0.71%
Distribution and service (12b-1) fees	0.25%	0.50%	None
Other expenses	0.14%	0.14%	0.14%
Total annual fund operating expenses	1.10%	1.35%	0.85%
Fee waiver and/or expense reimbursement1	0.15%	0.00%	0.03%
Total annual fund operating expenses after fee waiver and/or expense reimbursement	0.95%	1.35%	0.82%

Contractual arrangements have been made with the fund’s investment manager, Transamerica Asset Management, Inc. (“TAM”), through March 1, 2027 to waive fees and/or reimburse fund expenses to the extent that total annual fund operating expenses exceed 0.95% for Class R4 shares, 1.35% for Class R shares and 0.82% for Class I3 shares, excluding, as applicable, acquired fund fees and expenses, interest (including borrowing costs and overdraft charges), taxes, brokerage commissions, dividend and interest expenses on securities sold short, extraordinary expenses and other expenses not incurred in the ordinary course of the fund’s business. These arrangements cannot be terminated prior to March 1, 2027 without the Board of Trustees’ consent. TAM is permitted to recapture amounts waived and/or reimbursed to a class during any of the 36 months from the date on which TAM waived fees and/or reimbursed expenses for the class if the class’ total annual fund operating expenses have fallen to a level below the limits described above. In no case will TAM recapture any amount that would result, on any particular business day of the fund, in the class’ total annual operating expenses exceeding the applicable limits described above or any other lower limit then in effect.

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 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. The Example reflects applicable waivers and/or reimbursements for the duration of such arrangement(s). Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 year	3 years	5 years	10 years
Class R4	$97	$335	$592	$1,327
Class R	$137	$428	$739	$1,624
Class I3	$84	$268	$468	$1,046

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 portfolio turnover rate for the fund was 109% of the average value of its portfolio.

Principal Investment Strategies: The fund normally invests primarily in stocks of medium sized companies which the fund’s sub-adviser, Wellington Management Company LLP (the “sub-adviser”), believes will earn high returns on invested capital, benefit from long term secular growth trends, and meet the sub-adviser’s long term valuation criteria. Under normal circumstances, the sub-adviser invests at least 80% of the fund’s net assets (plus the amount of borrowings, if any, for investment purposes) in securities of medium sized (or mid-cap) companies and other investments with similar economic characteristics. The sub-adviser considers mid-cap companies to be companies with market capitalizations that, at the time of initial purchase, are within the range of capitalization of the companies that are included in the Russell Midcap® Growth Index1, a benchmark of the fund. As of December 31, 2025, the market capitalizations of companies in the Russell Midcap® Growth Index ranged from approximately $1.57 billion

to $101.87 billion. Over time, the capitalizations of the companies in the Russell Midcap® Growth Index will change. As they do, the size of the companies in which the fund invests may change.

The fund’s equity securities may include common stocks and preferred stocks listed on the New York Stock Exchange and on other national securities exchanges and, generally to a lesser extent, stocks that are traded over-the-counter. The fund normally emphasizes common stocks. The fund may also invest in foreign securities. Growth stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “value” stocks.

The fund may also invest its assets in cash, cash equivalent securities or short-term debt securities, repurchase agreements and money market instruments. Generally, 5% or less of the fund’s assets will be invested in cash and cash equivalents.

1 “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.

Principal Risks: Risk is inherent in all investing. Many factors and risks affect the fund's performance, including those described below. The value of your investment in the fund, as well as the amount of return you receive on your investment, may fluctuate significantly day to day and over time. You may lose part or all of your investment in the fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks (in alphabetical order after certain key risks) of investing in the fund. The relative significance of the key risks below may change over time and you should review each risk factor carefully. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. You may lose money if you invest in this fund.

Market – The market prices of the fund’s securities or other assets may go up or down, sometimes rapidly or unpredictably, due to factors such as economic events, inflation, changes in interest rates, governmental actions or interventions, actions taken by the U.S. Federal Reserve or foreign central banks, market disruptions caused by tariffs, trade disputes, labor strikes, supply chain disruptions or other factors, government shutdowns, political developments, civil unrest, acts of terrorism, armed conflicts, economic sanctions, countermeasures in response to sanctions, cybersecurity events, technological developments (such as artificial intelligence and machine learning) investor sentiment, the global and domestic effects of widespread or local health, weather or climate events, and other factors that may or may not be related to the issuer of the security or other asset. The market price of a security may also fall due to specific conditions that affect a particular sector of the securities market, a particular industry or a particular issuer or group of issuers. To the extent that securities of certain issuers behave or are perceived to behave similarly to each other, the market prices of those securities (or the market as a whole) may fall in response to a decline in the price of a particular security or group of securities. If the market prices of the fund’s securities and assets fall, the value of your investment in the fund could go down.

Economies and financial markets throughout the world are increasingly interconnected. Events or circumstances in one or more countries or regions could be highly disruptive to, and have

profound impacts on, global economies or markets. As a result, whether or not the fund invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the fund’s investments may go down.

The long-term consequences to the U.S. economy of the continued expansion of U.S. government debt and deficits are not known. Also, raising the ceiling on U.S. government debt and periodic legislation to fund the government have become increasingly politicized. Any failure to do either could lead to a default on U.S. government obligations, with unpredictable consequences for the fund’s investments, and generally for economies and markets in the U.S. and elsewhere.

Growth Stocks – Returns on growth stocks may not move in tandem with returns on other categories of stocks or the market as a whole. Growth stocks typically are particularly sensitive to market movements and may involve larger price swings because their market prices tend to reflect future expectations. When it appears those expectations may not be met, the prices of growth stocks typically fall. Growth stocks may also be more volatile because they often do not pay dividends. The values of growth stocks tend to go down when interest rates rise because the rise in interest rates reduces the current value of future cash flows. Growth stocks as a group may be out of favor and underperform the overall equity market for a long period of time, for example, while the market favors “value” stocks.

Medium Capitalization Companies – The fund will be exposed to additional risks as a result of its investments in the securities of medium capitalization companies. Investing in medium capitalization companies involves greater risk than is customarily associated with more established companies. The prices of securities of medium capitalization companies generally are more volatile and are more likely to be adversely affected by changes in earnings results and investor expectations or poor economic or market conditions, including those experienced during a recession, have more limited product lines, operating histories, markets or capital resources, may be dependent upon a limited management group, experience sharper swings in market values, or have limited liquidity. Securities of medium capitalization companies may underperform larger capitalization companies, may be harder to sell at times and at prices the portfolio managers believe appropriate and may offer greater potential for losses.

Focused Investing – To the extent the fund invests a significant portion of its assets in a limited number of countries, regions, sectors, industries or market segments, in a limited number of issuers, or in issuers in related businesses or that are subject to related operating risks, the fund will be more susceptible to negative events affecting those countries, regions, sectors, industries, segments or issuers, and the value of its shares may be more volatile than if it invested more widely.

Small Capitalization Companies – The fund will be exposed to additional risks as a result of its investments in the securities of small capitalization companies. Small capitalization companies may be more at risk than larger capitalization companies because, among other things, they may have limited product lines, operating history, market or financial resources, or because they may depend on limited management groups. Securities of small capitalization

companies are generally more volatile than and may underperform larger capitalization companies, may have limited liquidity, may be harder to sell at times and at prices the portfolio managers believe appropriate and may offer greater potential for losses.

Equity Securities – Equity securities generally have greater risk of loss than debt securities. Stock markets are volatile and the value of equity securities may go up or down, sometimes rapidly and unpredictably. The market price of an equity security may fluctuate based on overall market conditions, such as real or perceived adverse economic or political conditions or trends, tariffs and trade disruptions, wars, social unrest, inflation, substantial economic downturn or recession, changes in interest rates, or adverse investor sentiment. The market price of an equity security also may fluctuate based on real or perceived factors affecting a particular industry or industries or the company itself. If the market prices of the equity securities owned by the fund fall, the value of your investment in the fund will decline. The fund may lose its entire investment in the equity securities of an issuer. A change in financial condition or other event affecting a single issuer may adversely impact securities markets as a whole.

Sector Focus – To the extent the fund invests more heavily in a particular market sector, the value of the fund’s shares will be especially sensitive to developments that significantly affect that sector and there is increased risk that the fund will lose significant value if conditions adversely affect that sector. Individual sectors may be more volatile, and may perform differently, from the broader market.

Information Technology Sector – Information technology companies face intense competition and potentially rapid product obsolescence, including due to rapid development of technological innovations and frequent new product introduction. They may face unexpected risks and costs associated with technological developments, such as artificial intelligence and machine learning. Such companies are also heavily dependent on intellectual property rights and may be adversely impacted by the loss, impairment of, or inability to enforce those rights. They are also facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action. These companies may be developing or marketing new products or services for which markets are not yet established and may never become established.

Management – The value of your investment may go down if the investment manager’s or sub-adviser's judgments and decisions are incorrect or otherwise do not produce the desired results, or if the investment strategy does not work as intended. You may also suffer losses if there are imperfections, errors or limitations in the quantitative, analytic or other tools, resources, information and data used, investment techniques applied, or the analyses employed or relied on, by the investment manager or sub-adviser, if such tools, resources, information or data are used incorrectly or otherwise do not work as intended, or if the investment manager’s or sub-adviser's investment style is out of favor or otherwise fails to produce the desired results. Any of these things could cause the fund to lose value or its results to lag relevant benchmarks or other funds with similar objectives.

Active Trading – The fund may engage in active trading of its portfolio. Active trading will increase transaction costs and could detract from performance. Active trading may be more pronounced during periods of market volatility and may generate greater amounts of short-term capital gains.

Cybersecurity – Cybersecurity incidents, both intentional and unintentional, may allow an unauthorized party to gain access to fund assets, fund or shareholder data (including private shareholder information), or proprietary information, cause the fund or its service providers (including, but not limited to, the fund’s investment manager, any sub-adviser(s), transfer agent, distributor, custodian, fund accounting agent and financial intermediaries) to suffer data breaches, data corruption or loss of operational functionality, or prevent fund investors from purchasing, redeeming or exchanging shares, receiving distributions or receiving timely information regarding the fund or their investment in the fund. Cybersecurity incidents may render records of fund assets and transactions, shareholder ownership of fund shares, and other data integral to the functioning of the fund inaccessible, inaccurate or incomplete. The use of artificial intelligence and machine learning could exacerbate these risks. Cybersecurity incidents may result in financial losses to the fund and its shareholders, and substantial costs may be incurred in order to prevent or mitigate any future cybersecurity incidents.

Foreign Investments – Investing in securities of foreign issuers or issuers with significant exposure to foreign markets involves additional risks. Foreign markets can be less liquid, less regulated, less transparent and more volatile than U.S. markets. The value of the fund’s foreign investments may decline, sometimes rapidly or unpredictably, because of factors affecting the particular issuer as well as foreign markets and issuers generally, such as unfavorable government actions, including nationalization, expropriation or confiscatory taxation, reduction of government or central bank support, tariffs and trade disruptions, sanctions, political or financial instability, social unrest or other adverse economic or political developments. Foreign investments may also be subject to different accounting practices and different regulatory, legal, auditing, financial reporting and recordkeeping standards and practices, and may be more difficult to value than investments in U.S. issuers. Certain foreign clearance and settlement procedures may result in an inability to execute transactions or delays in settlement.

Large Shareholder – A significant portion of the fund’s shares may be owned by one or more investment vehicles or institutional investors. Transactions by these large shareholders may be disruptive to the management of the fund. For example, the fund may experience large redemptions and could be required to sell securities at a time when it may not otherwise desire to do so. Such transactions may increase the fund’s brokerage and/or other transaction costs. These transactions may also accelerate the realization of taxable capital gains to shareholders. In addition, sizeable redemptions could cause the fund’s total expenses to increase.

Liquidity – The fund may make investments that are illiquid or that become illiquid after purchase. Illiquid investments can be difficult to value, may trade at a discount from comparable, more liquid investments, and may be subject to wide fluctuations in value. Liquidity risk may be magnified in rising interest rate or volatile environments. If the fund is forced to sell an illiquid investment to meet redemption requests or other cash needs, the fund

may be forced to sell at a substantial loss or may not be able to sell at all. Liquidity of particular investments, or even entire asset classes, including U.S. Treasury securities, can deteriorate rapidly, particularly during times of market turmoil, and those investments may be difficult or impossible for the fund to sell. This may prevent the fund from limiting losses.

Preferred Stock – Preferred stocks may pay fixed or adjustable rates of return. Preferred stocks are subject to issuer-specific and market risks applicable generally to equity securities, but also risks associated with fixed-income securities, such as interest rate risk. A company’s preferred stocks generally pay dividends only after the company makes required payments to creditors, including holders of its bonds and other debt. As a result, the market prices of preferred stocks are typically more sensitive to changes in the issuer's creditworthiness than are the prices of debt securities. The market value of preferred stocks generally decreases when interest rates rise.

Repurchase Agreements – In a repurchase agreement, the fund purchases securities from a broker-dealer or a bank, called the counterparty, upon the agreement of the counterparty to repurchase the securities from the fund at a later date, and at a specified price. The securities purchased serve as the fund's collateral for the obligation of the counterparty to repurchase the securities. If the counterparty does not repurchase the securities, the fund is entitled to sell the securities, but the fund may not be able to sell them for the price at which they were purchased, thus causing a loss. If the counterparty becomes insolvent, there is some risk that the fund will not have a right to the securities, or the immediate right to sell the securities.

Valuation – Certain investments may be more difficult to value than other types of investments. The sales price the fund could receive for any particular portfolio investment may differ from the fund's valuation of the investment, particularly for securities that trade in thin or volatile markets, that are priced based upon valuations provided by third party pricing services, or that are valued using a fair value methodology. These differences may increase significantly and affect fund investments more broadly during periods of market volatility. Investors who purchase or redeem fund shares on days when the fund is holding fair-valued securities may receive fewer or more shares or lower or higher redemption proceeds than they would have received if the fund had not fair-valued securities or had used a different valuation methodology. The fund’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers. Fair value pricing involves subjective judgment, which may prove to be incorrect.

Performance: The bar chart and the table below provide some indication of the risks of investing in the fund. The bar chart shows how the fund’s performance has varied from year to year. The first index in the table shows how the fund’s average annual total returns for different periods compare to the returns of a broad measure of market performance. One or more secondary indices that the manager believes more closely reflect the market sectors and/or types of investments in which the fund invests also are used to measure the fund’s performance.

The fund acquired the assets and assumed the liabilities of three Transamerica Partners funds, including Transamerica Partners Institutional Mid Growth (the “predecessor fund”), on March 10, 2017, and the predecessor fund was the accounting and performance survivor of the reorganizations. This means that the predecessor fund's financial and performance history became the financial and performance history of the fund. In the reorganization of the predecessor fund, former shareholders of the predecessor fund received Class R4 shares of the fund. The performance of Class R4 shares includes the performance of the predecessor fund prior to the reorganizations, and has not been restated to reflect the annual operating expenses of Class R4 shares.

Absent any applicable fee waivers and/or expense limitations, performance would have been lower.

As with all mutual funds, past performance (before and after taxes) is not a prediction of future results. Updated performance information is available on our website at www.transamerica.com/investments-fund-center or by calling 1-888-233-4339.

Prior to December 1, 2018, the fund had a different sub-adviser and used different investment strategies. The performance set forth prior to that date is attributable to the previous sub-adviser and the investment strategies then in effect.

Annual Total Returns (calendar years ended December 31) - Class R4

	Quarter Ended	Return
Best Quarter:	6/30/2020	32.60%
Worst Quarter:	6/30/2022	-24.00%

Average Annual Total Returns (periods ended December 31, 2025)

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Class R4					11/7/2001
Return before taxes	7.38%	3.56%	9.31%
Return after taxes on distributions	1.19%	0.22%	6.32%
Return after taxes on distributions and sale of fund shares	6.83%	2.01%	6.69%
Class R (Return before taxes only)	7.02%	3.22%	N/A	8.04%	3/10/2017
Class I3 (Return before taxes only)	7.50%	3.71%	N/A	8.58%	3/10/2017
Russell 3000® Index1 (reflects no deduction for fees, expenses or taxes)	17.15%	13.15%	14.29%
Russell Midcap® Growth Index (reflects no deduction for fees, expenses or taxes)	8.66%	6.65%	12.49%

1 “Russell®” and other service marks and trademarks related to the Russell indexes are trademarks of the London Stock Exchange Group companies.

The after-tax returns are calculated using the historic highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns may depend on the investor’s individual tax situation and may differ from those shown. After-tax returns may not be relevant if the investment is made through a tax-exempt or tax-deferred account, such as a 401(k) plan.

After-tax returns are presented for only one class, and returns for other classes are presented before taxes only and will vary.

Management:

Investment Manager: Transamerica Asset Management, Inc. Sub-Adviser: Wellington Management Company LLP Portfolio Manager:
Timothy N. Manning	Portfolio Manager	since December 2018

Purchase and Sale of Fund Shares: Shares of the fund are available to individual and institutional investors through certain retirement plans. These plans include, but are not limited to, 401(k), 403(b) and 457 Plans, Money Purchase Plans, Profit Sharing Plans, Simplified Employee Pension Plans, Keogh Plans, defined benefit plans, nonqualified deferred compensation plans and IRAs. Shares may be purchased by these investors through a plan administrator, recordkeeper or authorized financial intermediary. If you are a participant in a plan, you should obtain the plan’s conditions for participation from your plan administrator. Shares of the fund are also available to other investors, including endowment funds and foundations, any state, county or city, or its instrumentality, department, authority or agency, and accounts registered to insurance companies, trust companies and bank trust departments. Such investors may purchase shares in the fund through the transfer agent directly. You may purchase shares of the fund on any day the New York Stock Exchange is open for business. Requests to purchase shares for the fund should be mailed to Transamerica Fund Services, Inc., P.O. Box 219945, Kansas City, MO 64121-9945. Participants in retirement plans administered by Transamerica Retirement Solutions should contact Transamerica Retirement Solutions at 1-800-755-5801 for additional information. If you would like to purchase shares in a fund by a wire transfer, please call 1-888-233-4339 for wire transfer instructions. You buy and redeem shares at the fund’s next-determined net asset value (“NAV”) after receipt of your request in good order. There is no minimum investment for eligible retirement plans investing in Class R shares. The minimum initial investment for Class R4 shares is $5,000. There is no minimum for subsequent investments in Class R or R4 shares. A retirement plan may, however, impose minimum investment requirements. Plan participants or IRA holders should consult their plan administrator, recordkeeper or authorized financial intermediary.

Redemption requests may be made by mail and, in certain circumstances, telephone. The proceeds of the redemption will be sent by mail or, if authorized on the Account Application, wire transfer. Requests to redeem shares of the fund should be mailed to Transamerica Fund Services, Inc., P.O. Box 219945, Kansas City, MO 64121-9945. You may redeem shares by telephone if you authorized telephone redemptions on your Account Application.

The fund reserves the right to refuse a telephone redemption request if it is believed it is advisable to do so. The telephone redemption option may be suspended or terminated at any time without advance notice.

Class I3 shares are only available to certain funds of funds, registered and unregistered insurance company separate accounts and collective investment trusts. Class I3 shares do not have a minimum initial investment for those that qualify for the share class or a minimum subsequent investment amount.

Tax Information: Fund distributions may be taxable as ordinary income, qualified dividend income, or capital gains, except when your investment is in an IRA, 401(k) or other tax-advantaged investment plan. In that case, you may be taxed when you take a distribution from such plan, depending on the type of plan, the circumstances of your distribution and other factors.

Payments to Broker-Dealers and Other Financial Intermediaries: If you purchase the fund through a broker-dealer or other financial intermediary, the fund and/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 intermediary and your salesperson to recommend the fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

In an effort to reduce paper mailings and conserve natural resources, we encourage you to visit our website, www.transamerica.com, to set up an account and enroll in eDelivery.

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