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S000000588 [Member] Investment Risks - Baron Partners Fund
Dec. 31, 2025
Common CEO Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Common CEO Risk. The Fund may invest in different companies that have certain persons in common, including the Chief Executive Officer or other person or persons fundamental to the success of the company. As a result, the Fund may be exposed to risks associated with an individual which may be greater than would be the case if measured only by investments on a per company basis. Notably, the Fund has made investments in SpaceX and Tesla, the Chief Executive Officer of each is Elon Musk. As such, the Fund may be considered to be exposed to risk associated with Mr. Musk.
Industry Concentration [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Industry Concentration. From time to time, market fluctuations in the value of the Fund’s investments, combined with the Fund’s non‑diversified portfolio, may result in the Fund being concentrated in the securities of a single issuer or a small number of issuers, including in a particular industry. As a result, the Fund will be particularly exposed to the risks of that company or industry relative to the risk exposure of investment companies holding a diversified portfolio of securities or those that seek to maintain near-index weightings in their portfolio securities. Accordingly, in those cases, the Fund will be disproportionately exposed to the market conditions, interest rates, and economic, regulatory, or financial developments that significantly affect that company or industry. For example, due to the size of the Fund’s investments in SpaceX and Tesla, which represent about 33% and 22%, respectively, of its net assets as of the date of this prospectus, the Fund will be adversely impacted by developments affecting the aerospace & defense, automotive and energy industries, as well as governmental environmental regulations. (Please see “Single or Related Issuers” in the “Principal Risks of Investing in the Fund” section.)
Leverage [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Leverage. The Fund borrows money from banks to buy securities and pledge its assets in connection with the borrowing. If the interest expense of the borrowing is greater than the return on the securities bought, the use of leverage will decrease the return to shareholders in the Fund. Use of leverage also tends to magnify the volatility of the Fund’s returns. The greater the use of leverage by the Fund, the greater the risk of the volatility of the Fund’s returns.
Growth Investing [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Growth Investing. Growth stocks can react differently to issuer, political, market and economic developments than the market as a whole and other types of stocks. Growth stocks tend to be more expensive relative to their earnings or assets compared to other types of stocks. As a result, because growth stocks tend to be sensitive to changes in their earnings and to increasing interest rates and inflation, they tend to be more volatile than other types of stocks. In response, from time to time, growth investing as an investment style may go out of favor with investors.
General Stock Market [Member]  
Prospectus [Line Items]  
Risk [Text Block]
General Stock Market. Fund losses may be incurred due to declines in one or more markets in which Fund investments are made. These declines may be the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s). In addition, turbulence as has recently been experienced, caused, among other reasons, by increased inflation, tightening monetary policy and interest rate increases by the US Federal Reserve or similar international bodies, and changes in U.S. trade policy. Reduced liquidity in financial markets may continue to negatively affect many issuers, which could have an adverse effect on your Fund investment. Events involving limited liquidity, defaults, non-performance or other adverse developments that affect one industry, such as the financial services industry, or concerns or rumors about any events of these kinds, have in the past and may in the future lead to market-wide liquidity problems, may spread to other industries, and could negatively affect the value and liquidity of the Fund’s investments. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market, such as Russia’s invasion of Ukraine in February 2022 and the world-wide response to it, have and may continue to adversely impact issuers and markets worldwide. Increasingly strained relations between countries, including between the U.S. and traditional allies and/or adversaries, could adversely affect U.S. issuers as well as non-U.S. issuers that rely on the United States for trade. A fund’s securities may be negatively impacted by inflation (or expectations for inflation), interest rates, global demand for particular products/services or resources, supply chain disruptions, natural disasters, pandemics, epidemics, terrorism, war, military confrontations, changes in trade regulations, elevated levels of government debt, internal unrest and discord, economic sanctions, regulatory events and governmental or quasi-governmental actions, among others. Ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, including the joint U.S.-Israeli strikes on Iran in February 2026, present considerable market risks, the ultimate effects of which are not known but could profoundly affect global economies and markets. Raising the ceiling on U.S. government debt has become increasingly politicized. Any failure to increase the total amount that the U.S. government is authorized to borrow could lead to a default on U.S. government obligations, with unpredictable consequences for economies and markets in the U.S. and elsewhere.
Financials Sector [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Financials Sector. The financials industries are subject to extensive government regulation, can be subject to relatively rapid change due to increasingly blurred
distinctions between service segments, and can be significantly affected by availability and cost of capital funds, changes in interest rates, the rate of corporate and consumer debt defaults, and price competition. Uncertainty in the banking and financial systems can result in significant and widespread deterioration in market and economic conditions by disrupting access to capital and other financial services, which could adversely affect the performance of the Fund.
Industrials Sector [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Industrials Sector. The Fund’s investments are exposed to issuers conducting business in the Industrials Sector. The Industrials Sector includes manufacturers and distributors of capital goods such as aerospace and defense, building projects, electrical equipment and machinery and companies that offer construction and engineering services. It also includes providers of commercial and professional services including printing, environmental and facilities services, office services and supplies, security and alarm services, human resource and employment services, research and consulting services. It also includes companies that provide transportation services. The Fund is subject to the risk that the securities of such issuers will underperform the market as a whole due to legislative or regulatory changes, adverse market conditions and/or increased competition affecting the Industrials Sector. The prices of the securities of companies operating in the Industrials Sector may fluctuate due to the level and volatility of commodity prices, the exchange value of the dollar, import controls, worldwide competition, liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control devices.
Consumer Discretionary Sectors [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Consumer Discretionary Sector. The consumer discretionary sector may be affected by changes in domestic and international economies, exchange and interest rates, inflation, competition, consumers’ disposable income, consumer preferences, social trends and marketing campaigns.
Risks of Emphasizing a Sector or Industry [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Risks of Emphasizing a Sector or Industry. If the Fund has invested a higher percentage of its total assets in a particular sector or industry, changes affecting that sector or industry may have a significant impact on the performance of the Fund’s overall portfolio. The economies and financial markets of certain regions — such as Latin America, Asia, and Europe and the Mediterranean region — can be interdependent and may all decline at the same time.
Small and Mid Sized Companies [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Small- and Mid-Sized Companies. The Adviser believes there is more potential for capital appreciation in small- and mid-sized companies, but there also may be more risk. Securities of small- and mid-sized companies may not be well known to most investors, and the securities may be less actively traded than those of large businesses. The securities of small- and mid-sized companies may fluctuate in price more widely than the stock market generally, and they may be more difficult to sell during market downturns. Small- and mid-sized companies rely more on the skills of management and on their continued tenure. Investing in small- and mid-sized companies requires a long-term outlook and may require shareholders to assume more risk and to have more patience than investing in the securities of larger, more established companies.
Single or Related Issuers [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Single or Related Issuers. Single or related issuers risk is the possibility that factors specific to an issuer or issuers to which the Fund is exposed will affect the market prices of such issuer’s securities. The performance of those issuers may have a greater effect on the Fund’s performance compared to a fund that has a greater diversity of investments in multiple issuers. Thus, a fund with concentrated investments in certain single issuers is more likely to experience significant fluctuations in value, exposing the Fund to a greater risk of loss in any given period. The Fund currently has significant investments in Space Exploration Technologies Corp. (“SpaceX”) and Tesla, Inc. (“Tesla”). As a result, the net asset value of the Fund will be materially impacted by the price of each issuer’s stock. Before investing in the Fund, investors should carefully consider publicly available information about SpaceX and Tesla. As long as the Fund maintains a substantial investment in these issuers, the Fund’s performance will be significantly affected by the performance of the stock and a decline in the price of Tesla or SpaceX stock could materially and adversely affect
your investment in the Fund. This risk may be amplified because these companies share the same Chief Executive Officer and major stockholder. See “Common CEO Risk.”
Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Fund losses may be incurred due to declines in one or more markets in which Fund investments are made.
Risk Nondiversified Status [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Non-Diversified Portfolio. The Fund is non-diversified, which means it will likely have a greater percentage of its assets in a single issuer than a diversified fund. As a result, a non-diversified fund will likely invest a greater percentage of its assets in fewer issuers, and the performance of those issuers may have a greater effect on the Fund’s performance compared to a diversified fund. Thus, a non-diversified fund is more likely to experience significant fluctuations in value, exposing the Fund to a greater risk of loss in any given period than a diversified fund.