Summary Prospectus by Investment Company (Form 497K)

Oberweis China Opportunities Fund

INVESTOR CLASS Ticker: OBCHX

INSTITUTIONAL CLASS Ticker: OCHIX

INVESTMENT OBJECTIVE

The Oberweis China Opportunities Fund's investment objective is to maximize long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

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.

​1 The Fund's adviser has a contractual arrangement with the Fund to reimburse it for total annual fund operating expenses in excess of 1.80% and 1.55% of average daily net assets excluding any interest, taxes, brokerage commissions, acquired fund fees and expenses and extraordinary expenses for Investor Class and Institutional Class shares, respectively, (the "expense limitation"). The contractual arrangement continues in force until April 30, 2027. Except with respect to termination, the contractual arrangement may be amended at any time by the mutual written consent of the adviser and the Fund, subject to the approval by the Board of Trustees of The Oberweis Funds.

Example

The 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. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. 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 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 127% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund invests, under normal circumstances, at least 80% of its net assets in China securities. Currently, China securities include 1) equity securities of companies that are organized under the laws of The People's Republic of China, Hong Kong or Taiwan or that are primarily traded on an exchange or over-the-counter in The People's Republic of China, Hong Kong or Taiwan; or 2) equity securities of companies that have at least 50% of their assets in The People's Republic of China, Hong Kong or Taiwan or that derive at least 50% of their revenues from business activities in The People's Republic of China, Hong Kong or Taiwan (collectively, referred to as "China") but which are listed and traded elsewhere.

The Fund invests principally in the common stocks of companies that the Fund's investment adviser, Oberweis Asset Management, Inc. ("OAM"), and sub-adviser, Oberweis Asset Management (Hong Kong) Limited (the "Sub-Adviser"), believe have the potential for significant long-term growth in market value. The Fund may invest in Chinese securities acquired through the Shanghai-Hong Kong Stock Connect and the Shenzhen-Hong Kong Stock Connect, as well as equity-linked certificates (also called Participatory Notes) which are expected to provide the fund exposure to certain classes of shares traded in foreign markets which would otherwise not be available to the Fund. The Fund may invest in equity-linked certificates issued and/or guaranteed by counterparties rated A or better by Moody's or Standard & Poor's Corporation or issued and/or guaranteed by counterparties deemed to be of similar quality by OAM. Equity-linked certificates are derivative securities generally issued by banks or broker-dealers that are linked to the performance of an underlying foreign security. The Fund may invest in equity-linked certificates linked to the performance of foreign securities in countries in which the Fund may invest, including but not limited to China. For purposes of the Fund's 80% investment policy, equity-linked certificates linked to the performance of China securities are considered China securities.

The Fund seeks to invest in those companies which OAM and the Sub-Adviser consider to have above-average long-term growth potential. OAM and the Sub-Adviser select companies which meet this criteria based on, among other things, fundamental analysis of individual securities. OAM and the Sub-Adviser's fundamental analysis entails an evaluation of an individual company's future growth prospects. OAM and the Sub-Adviser's evaluation may be based on, among other things, financial statement analysis, stock valuation in relation to the OAM and the Sub-Adviser's estimate of future earnings, evaluation of competitive product or service offerings, future research and development pipeline and management interviews.

OAM and the Sub-Adviser may actively trade the Fund's portfolio, and as a result, the Fund's portfolio turnover rate may be high. There are no restrictions on the capitalization of companies whose securities the Fund may buy.

The Fund seeks to invest in equity securities that typically exhibit the following characteristics:

Under-Appreciated Revenue and Earnings Growth - potential for revenue and/or earnings growth in excess of consensus expectations.

Timely Catalyst - a recent positive earnings release or an earnings surprise that tangibly and quantitatively begins to confirm that consensus analyst expectations are too low.

Inflection Point of Change - a business that is experiencing change - often from a new product, a new management team or a regulatory change - as these changes can drive unexpected or underestimated growth. A significant gap generally exists between OAM's forecasts and consensus analyst expectations.

Limited Analyst Coverage - a company not widely followed by other analysts to maximize the chances of finding misunderstood situations.

Sustainability - a sustainable business with a competitive position driven by niche market leadership, intellectual capital or unique manufacturing processes. Put another way, a reasonable barrier to competitive entry.

Operating Leverage - profitable and scalable business model, which tends to generate rising net profits margins as revenue growth accelerates.

Valuation - undervalued based on OAM's growth forecasts and historical valuation metrics afforded the company and/or peers.

PRINCIPAL RISKS

The biggest risk is that the Fund's returns may vary, and you could lose money by investing in the Fund. Because the Fund may invest substantially all of its assets in common stocks, the main risk is that the value of the stocks it holds might decrease in response to the activities of an individual company or in response to general market and/or economic conditions. If this occurs, the Fund's share price may also decrease.

The Fund is designed for long-term investors who seek growth of capital and who can tolerate the greater risks associated with seeking maximum capital appreciation. Investment in common stocks, particularly in common stocks of small- and medium-sized companies with high growth potential, can be volatile. The value of the Fund's shares will go up and down due to movement of the overall stock market or of the value of the individual securities held by the Fund. The value of each security held by the Fund may decline in response to conditions affecting the general economy; political, social, or economic instability at the local, regional, or global level; pandemics, epidemics and other similar circumstances in one or more countries or regions; and currency and interest rate fluctuations. Because of this volatility, we recommend that you invest in the Fund as a long-term investment only, and only for a portion of your investment portfolio, not for all of it. There can be no assurance that the Fund's objective will be met.

Equity Securities Risk

Equity securities are susceptible to general stock market fluctuations and to volatile increases and decreases in value. The equity securities held by the Fund may experience sudden, unpredictable drops in value or long periods of decline in value. This may occur because of factors affecting securities markets generally, or a particular company.

Risks Associated with Non-U.S. Companies

Investments by the Fund in the securities of non-U.S. issuers involve certain additional investment risks different from those of U.S. issuers. These risks include: possibility of political or economic instability of the country of issue, possibility of disruption to international trade patterns, possibility of currency risk, possibility of currency exchange controls, imposition of foreign withholding taxes, seizure or nationalization of foreign deposits or assets, and adoption of adverse foreign government trade restrictions. There may be less publicly available information about a non-U.S. company than about a U.S. company. Sometimes non-U.S. companies are subject to different accounting, auditing, and financial reporting standards, practices and requirements than U.S. companies. There is generally less government regulation of stock exchanges, brokers and listed companies abroad than in the U.S., which may result in less transparency with respect to a company's operations. The absence of negotiated brokerage in certain countries may result in higher brokerage fees.

Emerging Market Risks

In addition to the risks associated with non-U.S. companies in developing or emerging markets, there is a possibility of expropriation, nationalization, confiscatory taxation or diplomatic developments that could affect investments in those countries. In addition, political and economic structures in emerging markets countries may be new and developing rapidly, which may cause instability. Emerging markets countries are also more likely to experience high levels of inflation, deflation or currency devaluations, which could hurt their economies and securities markets.

Risks Associated with Chinese Companies

The Chinese economy is generally considered an emerging and volatile market. A small number of companies represent a large portion of the China market as a whole, and prices for securities of these companies may be very sensitive to adverse political, economic, or regulatory developments in China and other Asian countries, and may experience significant losses in such conditions. China's central government has historically exercised substantial control over the Chinese economy through administrative regulation and/or state ownership.

Despite economic reforms that have resulted in less direct central and local government control over Chinese businesses, actions of the Chinese central and local government authorities continue to have a substantial effect on economic conditions in China. These activities, which may include central planning, partial state ownership of or government actions designed to substantially influence certain Chinese industries, market sectors or particular Chinese companies, including halting IPOs, ousting company founders, passing laws that allow raids on private companies, and forcing companies to grant the Chinese Communist Party (CCP) significant power and influence within their operations, may adversely affect the public and private sector companies in which the Fund invests. Government actions may also affect the economic prospects for, and the market prices and liquidity of, the securities of China companies and the payments of dividends and interest by China companies. In addition, currency fluctuations, monetary policies, competition, social instability or political unrest may adversely affect economic growth in China. The Chinese economy and Chinese companies may also be adversely affected by regional security threats, as well as adverse developments in Chinese trade policies, or in trade policies toward China by countries that are trading partners with China. The occurrence of catastrophic events (such as hurricanes, earthquakes, pandemic disease, acts of terrorism and other catastrophes) in Greater China could also have a negative impact on the value of Chinese securities.

Due to restrictions on foreign ownership of Chinese companies imposed under Chinese law, Chinese companies that are listed in the U.S. typically do not offer common stock in the company itself to U.S. investors. Rather, Chinese companies typically offer shares of an offshore shell company (typically referred to as a "variable interest entity" or "VIE") that has entered into service and other contracts with the Chinese company. Accordingly, U.S. investors in Chinese companies listed on a U.S. stock exchange do not actually own shares of the Chinese company itself. The U.S.-listed shell company does not control the Chinese company and must rely on the Chinese company to perform its contractual obligations (which, as noted above, are governed by Chinese corporate and securities laws that are less protective of shareholders than U.S. laws). Moreover, the Chinese government may at any time invalidate or limit the contracts between a Chinese company and the offshore shell company which is offering shares in the U.S., which may result in the partial or total loss of the value of a U.S. investor's shares in the offshore shell company even if a direct investment in the Chinese company would retain value.

Chinese companies are required to follow Chinese accounting standards and practices, which only follow international accounting standards to a certain extent. However, the accounting, auditing and financial reporting standards and practices applicable to China's companies, including those listed on U.S. exchanges, may be less rigorous, and there may be significant differences between financial statements prepared in accordance with Chinese accounting standards and practice and those prepared in accordance with international accounting standards. In particular, the assets and profits appearing on the financial statements of a Chinese issuer may not reflect its financial position or results of operations in the way they would be reflected had such financial statements been prepared in accordance with U.S. Generally Accepted Accounting Principles. The quality of audits in China may be unreliable, which may require enhanced procedures. Consequently, the Fund may not be provided the same degree of protection or information as would generally apply in developed countries and the Fund may be exposed to significant losses. There is also substantially less publicly available information about Chinese issuers than there is about U.S. issuers. Therefore, disclosure of certain material information may not be made, and less information may be available to the Fund and other investors than would be the case if the Fund's investments were restricted to securities of U.S. issuers.

China's growth over the last several decades has also led to growing political and economic tensions with Taiwan, including China's stated intention to control Taiwan. Increased tensions or conflict between Taiwan and China poses significant risks to Chinese companies. Such an event could lead to the shuttering of China-focused funds, cancellation of foreign derivatives and other severe financial disruptions, leaving investors with little to no financial recourse.

Government Relationships Risk

While companies in Asia may be subject to limitations on their business relationships under applicable law, these laws may not be consistent with certain political and security concerns of the U.S. As a result, Asian companies may have material direct or indirect business relationships with governments that are considered state sponsors of terrorism by the U.S. government, or governments that otherwise have policies in conflict with the U.S. government (an "Adverse Government"). If the Fund invests in companies that have or develop a material business relationship with an Adverse Government, then the Fund will be subject to the risk that these companies' reputation and price in the market will be adversely affected.

Equity-linked Certificates Risk

Equity-linked certificates (also called Participatory Notes) are generally subject to the same risks as the foreign equity securities or the basket foreign securities they are linked to. Upon the maturity of the certificate, the holder generally receives a return of principal based on the capital appreciation of the linked security. If the linked security declines in value, the certificate may return a lower amount at maturity. The trading price of an equity-linked certificate also depends on the value of the linked security. Equity-linked certificates involve further risks associated with:

• purchases and sales of certificates, including the possibility that exchange rate fluctuations may negatively affect the value of a certificate,

• the credit quality of the certificate's issuer and/or guarantor, and

• liquidity risks and restrictions on transferability.

Ratings of issuers or guarantors of equity-linked certificates refer only to the issuer or guarantor's creditworthiness. They provide no indication of the potential risks of the linked securities.

RMB Currency Risk

The Fund may invest in Chinese securities acquired through the Shanghai-Hong Kong Stock Connect ("China Connect Securities") with Renminbi ("RMB"), the official currency of China. Similar to other foreign currencies, the exchange rate of the RMB may rise or fall. There is no guarantee that the RMB will not depreciate. The exchange rate of the

RMB may be affected by, among other things, foreign exchange controls imposed by the mainland Chinese central government from time to time (for example, there are currently restrictions on the conversion of the RMB into other currencies). The Fund may have to convert the dollar into RMB when investing in Chinese Connect Securities and vice versa for any payments in RMB from transactions in the China Connect Securities. The Fund may incur currency conversion costs (being the spread between buying and selling of the RMB) and subject to exchange rate fluctuation risks in any such currency conversion, which may adversely affect the market value of China Connect Securities.

Shanghai-Hong Kong Stock Connect Program (Stock Connect) Risk

China A-Shares listed and traded on certain Chinese stock exchanges through Stock Connect, a mutual market access program designed to, among other things, enable foreign investment in the People's Republic of China (PRC) via brokers in Hong Kong, are subject to a number of restrictions imposed by Chinese securities regulations and local exchange listing rules. Because Stock Connect was established in November 2014, developments are likely, which may restrict or otherwise affect the fund's investments or returns. Furthermore, any changes in laws, regulations and policies of the China A-Shares market or rules in relation to Stock Connect may affect China A-Share prices. These risks are heightened by the underdeveloped state of the PRC's investment and banking systems in general.

Geographic Concentration Risk

Investments in a single region, even though representing more than one country within the region, may be affected by common economic forces and other factors. This vulnerability to factors affecting China investments is significantly greater than it would be for a more geographically diversified fund, and may result in greater losses and volatility.

Portfolio Turnover Risk

In the past, the Fund has experienced high rates of portfolio turnover, which results in above average transaction costs and the payment by shareholders of taxes on above-average amounts of realized investment gains, including net short-term capital gains, which are taxed as ordinary income for federal income tax purposes when distributed.

FUND PERFORMANCE

The following bar chart and table provide some indication of the risks of investing in the Fund by showing how the performance of the Fund's Investor Class shares has varied over time. Of course, the Fund's past performance (before and after taxes) does not necessarily indicate how it will perform in the future. Updated performance information is available at oberweisfunds.com or by calling 800-245-7311.

Annual Total Returns

The table compares the Fund's average annual returns for the periods indicated to a broad-based securities market index. The table also shows returns on a before and after tax basis. 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 your individual tax situation and may differ from those shown. The after-tax return information shown does not apply to Fund shares held through a tax-advantaged account, such as a 401(k) plan or individual retirement account ("IRA"). After-tax returns are shown only for Investor Class and after-tax returns for Institutional Class will vary. In certain cases, the "Return After Taxes on Distributions and Sale of Fund Shares" may be higher than other return figures for the same period. This will occur when a capital loss is realized upon the sale of Fund shares and provides an assumed tax benefit that increases the return.

Average Annual Total Returns (for the Periods Ended December 31, 2025)

Oberweis China Opportunities Fund

​1 Since the inception of the institutional class on May 1, 2017.

MANAGEMENT

Investment Adviser

Oberweis Asset Management, Inc. ("OAM")

Subadviser

Oberweis Asset Management (Hong Kong) Limited

Portfolio Managers

James W. Oberweis, President, has managed the Fund since its inception.

Barry Wang, Portfolio Manager, has been a co-portfolio manager of the Fund since 2016.

Buying and Selling Fund Shares

Buying Investor Class Shares

The minimum initial investment is $1,000 ($500 for tax-advantaged retirement plans). You may reduce this $1,000 minimum initial investment by signing up for the Low Minimum Investment Plan. (See page 68 for details.) Additional purchases for all existing accounts must be in amounts of at least $100.

Buying Institutional Class Shares

The minimum initial investment is $1,000,000 ($100,000 for the Oberweis Focused International Growth Fund). There is no minimum for subsequent purchases. You may meet the minimum initial investment amount by aggregating multiple accounts with common ownership within a Fund, including individual and joint accounts, as well as accounts where you have beneficial ownership through acting as a custodian for a minor account or as a beneficiary to a trust account. In addition, if you invest in a Fund through a financial intermediary, the minimum initial investment requirement may be met if your financial intermediary aggregates investments of multiple clients to meet the minimum. There is no minimum initial investment requirement for omnibus retirement plans or wrap fee program assets held in an omnibus account with aggregate assets of $10 million or more. The Funds reserve the right to waive or modify these minimum initial investment requirements at any time.

Selling Shares

You may redeem shares of the Funds by mail, telephone, online at oberweisfunds.com or through your own securities broker/dealer or its designated agent or bank or other institution on any day the New York Stock Exchange is open.

Tax Information

Each Fund's distributions are taxable as ordinary income or capital gains (or a combination of both), unless your investment is in an IRA, 401(k) or other tax-advantaged investment plan (which may be taxable upon withdrawal).

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Funds through a broker-dealer or other financial intermediary (such as a bank), the Funds and their 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 to recommend the Funds over another investment. Ask your salesperson or visit your financial intermediary's Web site for more information.