How Mutual Funds Work and What You're Actually Buying

A mutual fund pools money from many investors to buy a basket of stocks, bonds, or other securities

When you buy a mutual fund, you are not buying individual stocks or bonds. You are buying a share of a fund that holds dozens, hundreds, or sometimes thousands of securities. A fund manager or a team of managers decides what to buy and sell within that fund. You own a piece of everything the fund owns, in proportion to how much of the fund you own.

Think of it like joining an investment club with thousands of other people. Instead of each person researching and buying individual stocks, one person (the manager) does the research and buying for everyone. Each member owns a slice of the whole portfolio. When the fund makes money from dividends or selling securities at a profit, that money is distributed to shareholders or reinvested automatically.

The price of a mutual fund share changes daily based on the total value of everything inside it. If the stocks and bonds the fund holds go up in value, the fund share price goes up. If they go down, so does the share price. You can buy or sell mutual fund shares through a brokerage account, and the transaction settles the next business day.

Key Takeaways

• A mutual fund holds a collection of securities, and you own a proportional share of the entire collection rather than individual holdings.
• A fund manager makes the buying and selling decisions, which is why you pay an annual fee (called an expense ratio) whether the fund makes money or loses it.
• Mutual funds are more diversified than owning a few individual stocks, but less diversified than owning an ETF with the same strategy, because ETFs typically have lower fees.
• Some mutual funds are actively managed (a manager picks the holdings) and others are index funds (they track a preset list like the S&P 500).
• You can buy mutual funds through most brokerages, and many employer retirement plans offer them as the primary investment choice.

Active management versus index funds

A actively managed mutual fund employs a manager or team who researches companies and decides which securities to buy and hold. The manager tries to beat the market by picking winners and avoiding losers. Because this requires research staff, trading costs, and the manager's salary, actively managed funds charge higher annual fees — often 0.5% to 2% of your investment per year.

An index mutual fund does not try to beat the market. Instead, it tracks a specific index — a preset list of securities. The most common is the S&P 500, which holds 500 large U.S. companies. The fund simply buys all the securities in that index in the same proportions. Because there is no active research or frequent trading, index funds charge much lower fees, typically 0.03% to 0.20% per year.

Over long periods, index funds have outperformed most actively managed funds, even after accounting for their lower fees. This is because beating the market consistently is harder than it sounds, and the high fees of active management eat into returns. However, some investors still prefer active management because they believe certain managers have genuine skill, or because they want someone making decisions on their behalf.

What you pay and when

The main cost of owning a mutual fund is the expense ratio — an annual percentage fee that comes out of the fund's assets automatically. If a fund has a 0.75% expense ratio and you own $10,000 of it, you pay $75 per year. You do not write a check; the fee is deducted from the fund's value before your share price is calculated.

Some mutual funds also charge a sales load, which is a commission paid when you buy or sell. A front-end load is charged when you buy (typically 3% to 6% of your investment). A back-end load is charged when you sell (typically 1% to 5%, declining over time). No-load funds charge no sales commission, though they may have higher expense ratios to compensate. Most investors buying through discount brokerages like Fidelity, Schwab, or Vanguard can find no-load options.

You may also owe capital gains taxes on distributions. When a fund sells a security at a profit, it must distribute that gain to shareholders. Even if you did not sell anything, you receive a taxable distribution. This is one reason index funds are often more tax-efficient than actively managed funds — they trade less frequently and generate fewer taxable events.

How mutual funds fit into a portfolio

Mutual funds are a straightforward way to own a diversified collection of securities without researching individual companies. A single fund can give you exposure to hundreds of stocks or bonds, which reduces the risk that one bad investment will hurt you badly. This is especially useful for people who do not have time to research individual securities or who prefer not to.

Many employer retirement plans (401(k)s and similar plans) offer mutual funds as the primary or only investment choice. In these plans, you typically choose from a menu of funds — perhaps a U.S. stock fund, an international stock fund, a bond fund, and a money market fund — and allocate your contributions among them. The plan administrator handles all the paperwork and tax reporting.

If you are choosing between mutual funds and ETFs that track the same index, the ETF usually wins on cost. ETFs typically have lower expense ratios and no sales loads. However, mutual funds may be more convenient if you are investing through an employer plan or if you want to set up automatic monthly contributions, since some mutual funds allow this directly while ETFs do not.

Mutual funds in taxable accounts versus retirement accounts

In a taxable brokerage account, you pay capital gains tax on distributions and on any profit when you sell. This makes actively managed funds less attractive, because their frequent trading generates more taxable events. Index funds are more tax-efficient in taxable accounts because they trade less often.

In a retirement account (such as a traditional IRA, Roth IRA, or 401(k)), you do not pay tax on distributions or gains while the money is in the account. This makes the tax efficiency of the fund less important, because you are not paying tax on those gains anyway. You can own actively managed funds in retirement accounts without worrying about annual tax bills. However, you still pay the expense ratio, so lower-cost index funds remain the better choice for most people.

How to buy mutual funds

You can buy mutual funds through most brokerages — Fidelity, Schwab, Vanguard, E*TRADE, and others all offer them. You open a brokerage account, fund it with cash, and then place an order to buy shares of the fund you want. The order settles the next business day, and the shares appear in your account.

If you are buying through an employer retirement plan, the process is simpler. You log into your plan's website, choose from the menu of available funds, and specify how much of your paycheck to invest in each one. The plan administrator handles everything else. You can change your allocation at any time, though some plans limit changes to once per quarter or once per year.

You can also set up automatic monthly investments in mutual funds through most brokerages. This is called dollar-cost averaging, and it means you buy more shares when the price is low and fewer when the price is high, which can reduce the impact of market timing on your returns.

Mutual funds versus other investment types

A mutual fund is actively or passively managed, charges an annual expense ratio, and settles the next business day. An ETF is similar but typically has lower fees, trades like a stock during market hours, and is often more tax-efficient. For most investors, an ETF tracking the same index as a mutual fund is the better choice because of lower costs.

A stock is a single company's ownership share. It requires you to research individual companies and decide which ones to buy. A mutual fund or ETF does that research for you (or tracks an index automatically). Owning individual stocks gives you more control but requires more work and carries more risk if you pick poorly.

A REIT (real estate investment trust) is similar to a mutual fund but holds real estate properties or mortgages instead of stocks and bonds. A bond fund is a mutual fund that holds bonds instead of stocks. Both are types of mutual funds, just with different underlying assets.

Frequently Asked Questions

Can I lose all my money in a mutual fund?

You can lose a significant portion of your investment if the securities the fund holds fall in value. However, it is extremely unlikely you will lose everything unless the fund holds very risky assets (like penny stocks or leveraged derivatives). A diversified mutual fund holding hundreds of stocks or bonds is much safer than owning a single stock.

What happens if the fund manager leaves?

The fund company hires a new manager to replace them. This can affect performance if the new manager has a different investment style or less skill. You can switch to a different fund if you are unhappy with the change, though you may owe capital gains tax if you are in a taxable account.

Do I have to hold a mutual fund for a certain amount of time?

No. You can buy and sell mutual fund shares whenever you want. However, some funds charge a redemption fee if you sell within a short period (typically 30 to 90 days). Check the fund's prospectus to see if this applies. In retirement accounts, there are no restrictions on buying and selling, only on withdrawing the money itself.

Why would I choose an actively managed fund over an index fund?

Some investors believe certain managers have genuine skill and can beat the market over time. Others prefer having someone make investment decisions on their behalf rather than owning a preset list. However, most actively managed funds underperform index funds over 10+ year periods, even before accounting for higher fees.

Can I use mutual funds in a 401(k)?

Yes. Most 401(k)s offer a menu of mutual funds as investment choices. You choose which funds to invest in and how much of your paycheck goes to each one. The plan administrator handles all the paperwork, and you do not pay capital gains tax on distributions while the money is in the account.