Financial Basics · Investing Fundamentals

Mutual Funds

Definition

A mutual fund pools money from many investors to buy a portfolio of stocks, bonds, or both. Shares are priced once per day at the net asset value (NAV).

Why it matters in retirement

Most 401(k) plans still offer mutual funds, not ETFs — so understanding fees and share classes is essential. The difference between a 0.04% index fund and a 1.2% actively managed fund can cost a retiree over $100,000 on a $500,000 balance over 20 years.

Key Numbers — 2026

Vanguard Total Market Index
0.04%
Avg active fund expense ratio
0.66%
Target-date fund avg ER
0.32%
Front-load max (Class A)
5.75%

Pros

  • Professionally managed
  • Automatic reinvestment
  • 401(k) availability
  • Fractional shares

Cons

  • Higher fees than ETFs
  • Less tax-efficient
  • Only priced once per day
  • Load funds charge sales commissions

Common mistakes

  • Paying a front-end load when a no-load alternative exists
  • Holding bond funds in a taxable account instead of tax-advantaged
  • Chasing last year's top performer
  • Not knowing your fund's true "all-in" expense (ER + 12b-1 + transaction costs)

Related

ETFs (Exchange-Traded Funds)

An ETF is a basket of securities (stocks, bonds, or both) that trades on an exchange like a single stock. Most ETFs passively track an index…

Index Funds

An index fund is a mutual fund or ETF that tries to match — not beat — a market index like the S&P 500 or Total US Stock Market. No active m…

401(k)

A 401(k) is an employer-sponsored retirement plan that lets employees defer pre-tax (or Roth) salary into an investment account. Most employ…

IRA

An Individual Retirement Account (IRA) is a self-directed retirement account with tax advantages. Traditional IRAs offer pre-tax contributio…

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