What Is a Mutual Fund?
A mutual fund pools money from thousands of investors and hands it to a professional manager who invests according to a stated strategy, such as large-cap U.S. stocks, investment grade bonds, or a balanced mix. Each investor owns shares representing a proportional slice of the whole portfolio.
Mutual funds come in active varieties, where managers pick securities trying to beat a benchmark, and passive varieties, where the fund simply tracks an index. They remain the backbone of retirement investing, especially inside 401(k) plans.
How Mutual Funds Work
Unlike stocks or ETFs, mutual fund shares do not trade during the day. All purchases and redemptions execute once daily at the fund's net asset value, or NAV, which is calculated after the market closes as: NAV = (Total Assets - Liabilities) / Shares Outstanding.
Investors pay an expense ratio, an annual percentage of assets that covers management and operations. Active equity funds commonly charge 0.5 to 1.0 percent or more, while passive index mutual funds can charge under 0.1 percent, and some funds add sales charges called loads.
Example
Suppose a fund holds 505 million dollars of securities, owes 5 million dollars in expenses, and has 25 million shares outstanding. Its NAV is (505 - 5) / 25 = 20 dollars per share, so an investor placing a 4,000 dollar order that day receives 200 shares.
If the fund charges a 0.8 percent expense ratio, that investor pays about 32 dollars per year on a 4,000 dollar balance, deducted gradually from the fund's assets rather than billed directly.
Why It Matters
Mutual funds manage tens of trillions of dollars globally and are how most households actually own the market, making their flows a powerful force in asset prices. The active versus passive debate, and the persistent difficulty active managers face beating their benchmarks after fees, is one of the defining stories of modern investing.
Asset management is also a major buy-side career path, with portfolio managers and research analysts at mutual fund companies serving as key clients for sell-side equity research and trading desks.
