Financial Basics · Investing Fundamentals

ETFs (Exchange-Traded Funds)

Definition

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 at very low cost.

Why it matters in retirement

ETFs made diversified, low-cost investing accessible to everyone. A single ETF can give you exposure to thousands of stocks for an annual fee of 0.03–0.20%. For retirees, that fee difference compounds into tens of thousands of dollars over 20+ years.

Key Numbers — 2026

Total US market ETF expense
0.03%
Total bond market ETF expense
0.03%
Avg active mutual fund expense
0.66%
1% fee over 30 years
~28% less wealth

Pros

  • Ultra-low fees
  • Tax-efficient (in-kind redemptions minimize capital gains)
  • Instant diversification
  • Trades like a stock — intraday liquidity

Cons

  • Can be traded too frequently
  • Niche/leveraged ETFs carry significant risk
  • Bid-ask spreads on small ETFs

Common mistakes

  • Paying 0.50%+ for a "smart beta" ETF instead of 0.03% for a plain index
  • Buying leveraged/inverse ETFs expecting them to work long-term
  • Ignoring bid-ask spreads on thinly traded ETFs
  • Treating ETFs like trading vehicles instead of long-term holdings

Related

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…

Mutual Funds

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 …

Stocks

A stock is a fractional ownership share in a publicly traded company. Stockholders benefit when the business grows (price appreciation) and,…

Bonds

A bond is a loan you make to a government or corporation. In exchange, the issuer pays you periodic interest (coupon) and returns your princ…

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