What is a mutual fund?

A mutual fund pools money from many investors to buy a diversified portfolio of stocks, bonds, or other securities. When you invest $1,000 in a mutual fund, your money is combined with thousands of other investors' money to purchase a share of all the underlying securities. Mutual funds are priced once per day after market close (unlike ETFs, which trade throughout the day). They are one of the most common investments in 401(k) plans and IRAs. The US mutual fund industry manages over $27 trillion in assets.

What is the difference between a mutual fund and an ETF?

Both mutual funds and ETFs hold diversified portfolios, but they differ in how they trade. Mutual funds are priced once per day at net asset value (NAV) after market close — you buy or sell at that end-of-day price. ETFs trade like stocks throughout the day at market prices. Most index ETFs have lower expense ratios than mutual funds, but the difference has narrowed — Fidelity's ZERO funds charge 0% expense ratio, the same as the cheapest ETFs. For 401(k) investors, mutual funds are typically the only option; for taxable brokerage accounts, ETFs are often more tax-efficient.

Are index funds better than actively managed mutual funds?

Research strongly favors index funds for most investors. The SPIVA (S&P Indices vs. Active) report consistently shows that over 80–90% of actively managed large-cap US funds underperform their benchmark index over 10-year periods, after accounting for fees. Actively managed funds charge higher expense ratios (0.5–1.5%) vs. index funds (0.03–0.20%), and these costs compound over decades. However, some active funds outperform — particularly in less efficient markets (small-cap, international, fixed income) where active research adds more value.

How much does it cost to invest in mutual funds?

The primary cost is the expense ratio — an annual fee deducted from fund assets as a percentage of assets under management. Index mutual funds: 0.03–0.20% (e.g., Vanguard VFIAX charges 0.04%; Fidelity ZERO index funds charge 0%). Actively managed funds: 0.5–1.5% typically; some specialty funds charge 1.5–2%+. Sales loads (commission to a broker): 0–5.75% upfront (Class A shares) — most no-load funds at Fidelity, Vanguard, Schwab have no sales loads. Always choose no-load funds.

Can I invest in mutual funds with a small amount of money?

Yes. Many mutual funds have been lowering or eliminating minimums. Fidelity's ZERO index funds (FZROX, FZILX) have no minimum investment. Vanguard's Admiral Shares (VFIAX, VBTLX) have $3,000 minimums. Schwab's index mutual funds (SWTSX, SWPPX) have no minimum. If you have a 401(k), minimums typically don't apply — you can invest any amount through your payroll contribution. For IRAs, you can start with as little as $1 at most major brokerages.

How to Invest in Mutual Funds 2026 — Beginner's Step-by-Step Guide

A mutual fund pools money from thousands of investors to buy a diversified portfolio of stocks, bonds, or other securities — managed by a professional fund company. In 2026, the best mutual funds for most investors are low-cost index mutual funds that track the S&P 500, total stock market, or bond market. Over 80% of actively managed funds underperform their index benchmarks over 10 years, after fees.

Quick answer: The best mutual fund strategy for most investors is buying a low-cost total market index fund (FZROX, VTSAX, or SWTSX) or S&P 500 index fund (FXAIX, VFIAX, or SWPPX) with an expense ratio under 0.10%. In a 401(k), pick the S&P 500 or total market index fund with the lowest expense ratio available.

How Mutual Funds Work

When you invest in a mutual fund:

You buy shares at the fund’s Net Asset Value (NAV) — priced once per day after market close (4:00 PM ET)
Your money is pooled with other investors’ money
The fund manager (index funds: passive tracking; active funds: human manager) buys securities
You receive proportional ownership of all underlying securities
Dividends and interest are passed through to you (or reinvested)
Capital gains may be distributed annually (a taxable event in non-retirement accounts)

Index Funds vs. Actively Managed Funds

Feature	Index Mutual Fund	Actively Managed Fund
Manager’s goal	Match an index (S&P 500, total market)	Beat the index
Expense ratio	0.03–0.20%	0.5–1.5%+
Turnover	Low (10–20%/year)	High (50–100%+/year)
Tax efficiency	High	Lower (more distributions)
Performance vs benchmark	Matches index (minus fee)	80–90% underperform long-term
Predictability	High	Low

The math on costs: On a $100,000 investment over 30 years at 7% growth:

Index fund (0.05% expense ratio): ~$760,000
Active fund (1.0% expense ratio): ~$620,000

The 0.95% difference in fees costs approximately $140,000 over 30 years.

Best Index Mutual Funds in 2026

US Total Stock Market Index Funds

Fund	Ticker	Expense Ratio	Minimum	Provider
Fidelity ZERO Total Market	FZROX	0.00%	$0	Fidelity
Schwab Total Stock Market	SWTSX	0.03%	$0	Schwab
Vanguard Total Stock Market Admiral	VTSAX	0.04%	$3,000	Vanguard

S&P 500 Index Funds

Fund	Ticker	Expense Ratio	Minimum	Provider
Fidelity 500 Index Fund	FXAIX	0.015%	$0	Fidelity
Fidelity ZERO Large Cap	FNILX	0.00%	$0	Fidelity
Vanguard 500 Index Admiral	VFIAX	0.04%	$3,000	Vanguard
Schwab S&P 500 Index	SWPPX	0.02%	$0	Schwab

International Index Funds

Fund	Ticker	Expense Ratio	Coverage
Fidelity ZERO International	FZILX	0.00%	International ex-US
Vanguard Total Intl Stock Admiral	VTIAX	0.12%	Total international
Schwab International Index	SWISX	0.06%	Developed markets

Bond Index Funds

Fund	Ticker	Expense Ratio	Coverage
Vanguard Total Bond Market Admiral	VBTLX	0.05%	US bonds
Fidelity US Bond Index	FXNAX	0.025%	US bonds
Schwab US Aggregate Bond	SWAGX	0.04%	US bonds

Step-by-Step: How to Invest in Mutual Funds

Step 1: Choose where to buy

In a 401(k): Mutual funds are already your primary option. Select the S&P 500 or total market index fund with the lowest expense ratio from your plan’s fund menu.

In an IRA or taxable brokerage: Open an account at Fidelity, Vanguard, or Schwab — all offer free accounts with no investment minimums on their own index funds.

Step 2: Choose your fund(s)

For most investors, one of these three approaches works:

Option A — One-fund approach: Total stock market index fund (VTSAX, FZROX). Simple, highly diversified, all-equity.

Option B — Three-fund portfolio:

60% US total stock market (VTSAX or FZROX)
30% International stocks (VTIAX or FZILX)
10% US bonds (VBTLX or FXNAX)

Option C — Target date fund: All-in-one fund that automatically adjusts allocation over time. Vanguard Target Retirement 2055 (VFFVX), Fidelity Freedom 2055 (FDEEX). Expense ratios 0.10–0.17%. Ideal for set-and-forget investors.

Step 3: Check costs before buying

Look for:

Expense ratio — aim for under 0.20% for index funds
Sales loads — avoid any fund with a front-end or back-end load
Transaction fees — most brokerages waive these for their own funds

Step 4: Fund your account

IRA: Annual contribution limit is $7,000 in 2026 ($8,000 if age 50+)
401(k): Annual employee contribution limit is $23,500 in 2026 ($31,000 if age 50+)
Taxable account: No contribution limits

Step 5: Automate contributions

Set up automatic monthly transfers. Consistency over time — dollar-cost averaging — reduces timing risk and builds wealth systematically.

Mutual Funds in a 401(k) — What to Look For

Most 401(k)s offer 10–30 mutual fund options. To pick the right ones:

Find the S&P 500 or total market index fund
Compare expense ratios — pick the lowest
Avoid target date funds with expense ratios above 0.20%
Never pay a load (sales commission) inside a 401(k)

If your 401(k) has no index fund options (only high-fee active funds), contribute enough to get the employer match, then max your IRA at Fidelity/Vanguard before contributing more to the 401(k).

How Mutual Funds Are Taxed

Account Type	Tax Treatment
401(k) Traditional	Tax-deferred — pay income tax on withdrawals
IRA Traditional	Tax-deferred — pay income tax on withdrawals
Roth IRA	Tax-free growth — no tax on qualified withdrawals
Taxable brokerage	Dividends and capital gains distributed are taxable yearly

Tax drag: Active funds distribute more capital gains than index funds, creating taxable events even if you don’t sell. Hold active funds in tax-advantaged accounts (IRA, 401k); hold ETFs in taxable accounts for efficiency.

Written by WealthVieu

WealthVieu researches and writes data-driven personal finance guides using primary sources including the IRS, Bureau of Labor Statistics, Federal Reserve, and Census Bureau.

The content on Wealthvieu is for informational purposes only and should not be considered financial, tax, or investment advice. Consult a qualified professional before making financial decisions. Full disclaimer · Editorial policy