Mutual Fund Basics Guide
A mutual fund pools money from many investors to buy a diversified portfolio of stocks, bonds, or other securities. Unlike individual stock picking, mutual funds offer instant diversification and professional management for a low minimum investment.
Mutual funds are one of the most popular investment vehicles in the United States, with over $23 trillion in assets under management as of 2025. When you buy shares of a mutual fund, you become a partial owner of every security the fund holds. The fund's net asset value (NAV) is calculated once per day after market close, and all buy and sell orders are executed at that single price.
Compared to individual stocks, mutual funds reduce company-specific risk through diversification. Compared to ETFs, mutual funds allow fractional share purchases and typically support automatic investment plans. The Vanguard Total Stock Market Index Fund (VTSAX), for example, holds more than 3,500 U.S. stocks with a single expense ratio of 0.04%, making it one of the most efficient ways to own the entire U.S. equity market.
How Mutual Funds Work
Each mutual fund has an investment objective outlined in its prospectus. Fund managers buy and sell securities within the portfolio to meet that objective. The fund's performance is reported as the change in NAV plus any distributions. Investors can typically buy into a fund with as little as $500 to $3,000 for actively managed funds, or $1 for many index funds. The Fidelity ZERO Total Market Index Fund (FZROX) requires no minimum and charges no expense ratio, demonstrating how low-cost indexing has reshaped the industry.
Mutual funds distribute capital gains and dividends to shareholders annually. These distributions are taxable in taxable accounts, which is why tax-efficient fund placement matters. Funds also charge ongoing operating expenses, expressed as the expense ratio, which directly reduces returns. A fund with a 1% expense ratio will consume roughly 18% of your potential portfolio value over 30 years compared to a 0.05% fund, assuming 6% annual returns.
FAQs
What is the minimum investment for most mutual funds?
Minimums vary by fund family. Vanguard requires $3,000 for most actively managed funds and $1,000 for target-date funds, though many index funds like VTSAX have $3,000 minimums. Fidelity and Schwab offer funds with $0 minimums, such as FZROX and SWTSX. Retirement accounts sometimes have lower minimums.
Can I lose money in a mutual fund?
Yes. Mutual funds are subject to market risk. A stock fund can lose 30-50% in a severe bear market, as seen in 2008 when the S&P 500 fell 38%. However, diversification across many securities reduces the impact of any single company's failure. Bond funds also carry interest rate and credit risk.
How are mutual funds different from ETFs?
Mutual funds trade once per day at NAV, while ETFs trade intraday on exchanges like stocks. Mutual funds support automatic investing and fractional shares natively, whereas ETFs require a brokerage and may trade at premiums or discounts to NAV. ETFs are generally more tax-efficient due to the in-kind creation/redemption mechanism.