FXAIX vs VOO: Fidelity Mutual Fund or Vanguard ETF?
Same index, different fund structures. FXAIX is a mutual fund (Fidelity 500 Index Fund), VOO is an ETF. The choice is mostly determined by what account you're using and what platform.
FXAIX is cheaper (0.015% vs 0.03%) and ideal inside a Fidelity 401(k) or IRA. VOO is more tax-efficient for taxable brokerage accounts (ETFs avoid forced capital gains distributions). Buy FXAIX at Fidelity in tax-advantaged; buy VOO anywhere in taxable.
Quick stats
| Metric | FXAIX | VOO |
|---|---|---|
| Price | $247.64 | $652.78 |
| TTM yield | 1.10% | 1.09% |
| Real yield (NAV-adj.) | 1.52% | 1.51% |
| NAV change (period) | 38.2% | 38.2% |
| Annualized volatility | 1326.6% | 1327.2% |
| Distribution frequency | quarterly | quarterly |
| Expense ratio | 0.01% | 0.03% |
| Inception | 1988-02-17 | 2010-09-07 |
| AUM | ~$600B | ~$500B |
| 1Y dividend CAGR | 4.1% | 5.4% |
| 3Y dividend CAGR | 5.5% | 5.9% |
| 5Y dividend CAGR | 4.9% | 5.9% |
| 5Y price CAGR | 11.4% | 11.3% |
Strategy & holdings
Both track the S&P 500 and hold the same stocks. The structural difference — mutual fund vs ETF — drives everything: trading mechanics, tax treatment, minimum investments, and availability on different platforms.
Mutual fund tracking the S&P 500. Trades once daily at NAV. No minimum investment at Fidelity.
ETF tracking the S&P 500. Trades intraday on exchanges. In-kind creation/redemption avoids most capital gains distributions.
FXAIX has the lower expense ratio — half of VOO's. Inside a tax-advantaged account this is a clear win. The problem is in taxable accounts: mutual funds must distribute realized capital gains to all shareholders annually, which can force unexpected taxable events. ETFs use in-kind creation/redemption to avoid most of these distributions. Over 20 years in a taxable account, VOO's structural tax advantage can easily outweigh FXAIX's 1.5 bps expense ratio edge.
Yield & distributions
Yields are essentially identical (1.2-1.5%) because both hold the same S&P 500 stocks. FXAIX pays semi-annually vs VOO's quarterly — a minor operational difference but no actual yield difference.
Total return & NAV
Total returns track within a few basis points annually. FXAIX wins by the expense ratio difference (~1.5 bps); VOO wins back some of that from tax efficiency in taxable accounts. Over multi-decade horizons these small edges compound but the practical difference is tiny.
Risk & volatility
Both are pure S&P 500 exposure. No meaningful risk difference.
Tax treatment
This is the only place where the choice actually matters. In a 401(k) or IRA, taxes don't apply and FXAIX's lower expense ratio wins. In a taxable brokerage account, VOO's ETF structure avoids forced capital gains distributions, which can be worth more than the expense ratio difference over time.