beginner
7 min read

What is a Mutual Fund? How They Work

Mutual funds explained: structure, types, fees, and how they compare to ETFs.

What Is a Mutual Fund?

A mutual fund pools money from many investors to buy a diversified portfolio of stocks, bonds, or other assets. You buy shares; the fund's value (NAV) is calculated at the end of each trading day.

How They Work

  • NAV (Net Asset Value): Total value of fund holdings ÷ number of shares. Calculated daily.
  • Trading: You buy or sell at the end-of-day NAV. Orders placed during the day execute at that day's closing price.
  • Professional management: Active funds have managers picking investments; index funds track an index automatically.

Types of Mutual Funds

  • Stock funds: Equity focus
  • Bond funds: Fixed income
  • Index funds: Track S&P 500, total market, etc.
  • Target-date funds: Automatically adjust allocation as you approach retirement

Fees to Watch

  • Expense ratio: Annual cost as % of assets. Look for under 0.5% (lower is better).
  • Loads: Sales charges. Avoid front-end or back-end loads when possible.
  • 12b-1 fees: Marketing costs. Prefer funds without them.

Mutual Fund vs. ETF

Mutual funds trade once per day; ETFs trade intraday. Mutual funds often have minimums; ETFs need 1 share. In 401(k)s, you'll usually see mutual funds.

Frequently Asked Questions

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What is a Mutual Fund? How They Work | Investors Lab | Investors Lab