RI
RetailInvestor

Index Fund vs ETF: What Is the Difference?

Compare index funds and ETFs.

Feature
Index Fund (Mutual Fund)
Index ETF
Expense Ratio
0.015-0.15%
0.03-0.10%
Trading
End of day NAV
Real-time market hours
Tax Efficiency
Good
Better
Minimum
$0-$3,000
1 share (~$1 fractional)
Auto-Invest
Easy
Limited

Index Fund (Mutual Fund)

Advantages

  • +Easy dollar-amount investing
  • +Automatic investment setup
  • +No bid-ask spread
  • +Identical returns to ETF equivalent

Disadvantages

  • -Trade once daily
  • -Often require minimums ($1,000+)
  • -Less tax efficient

Best For:

Automatic investing, retirement plans, set-and-forget

Index ETF

Advantages

  • +Trade anytime
  • +Lower expense ratios
  • +More tax efficient
  • +No minimums
  • +Greater flexibility

Disadvantages

  • -Bid-ask spread
  • -Must buy whole shares (usually)
  • -Temptation to trade

Best For:

Cost-sensitive investors, taxable accounts, flexible trading

The Bottom Line

Index funds and index ETFs often track the same benchmark and have nearly identical returns. The differences are structural: how you buy them, minimum investments, and tax treatment. For most people, either works great. If auto-investing matters, index mutual funds are convenient. If costs matter most, index ETFs win.

Related Resources

Frequently Asked Questions

Get Smarter About Investing

Free weekly market insights, calculator updates, and investing education.