FZROX vs. FXAIX: Fidelity ZERO Total Market I or Fidelity 500 Index Fund?
Figures last verified October 31, 2026
An all-Fidelity question: the zero-fee total market fund, or the near-zero S&P 500 fund? It's really two questions — total market vs. large-cap, and free-but-trapped vs. cheap-but-portable.
| FZROX | FXAIX | |
|---|---|---|
| Fund | Fidelity ZERO Total Market Index Fund | Fidelity 500 Index Fund |
| Family | Fidelity | Fidelity |
| Category | Total US Market | S&P 500 / Large Blend |
| Type | Index | Index |
| Expense ratio | 0.00% | 0.015% |
| Cost per $10k/yr | $0 | $1.50 |
| Minimum | $0 | $0 |
| Strategy | Tracks Fidelity's proprietary US Total Investable Market Index — about 2,700 stocks — at a 0.00% expense ratio. | Tracks the S&P 500 index of the 500 largest US companies. |
FZROX owns the whole market for free but can't leave Fidelity in kind; FXAIX is the S&P 500 for 0.015% and travels. In an IRA, FZROX. In taxable, FXAIX (or an ETF). The total-market-vs-500 difference matters more than the fee.
About FZROX
The expense ratio is zero. Not low — zero. When Fidelity launched the ZERO funds in 2018 it was a marketing shot at Vanguard, and nearly eight years on, the funds have done what they promised: tracked the broad US market at no cost, with performance right on top of VTSAX and FSKAX. The free lunch, in this narrow case, is real.
About FXAIX
FXAIX is what happens when index investing becomes a commodity and price wars do their work: the S&P 500, tracked with surgical precision, for 0.015% — a dollar fifty per year on a $10,000 balance — with no minimum investment. There is no catch in the fund itself. Fidelity loses money or close to it here and earns it back when you eventually use their other services.
Whichever you pick, the principle is the same one that runs through this whole site: minimize cost, hold for decades, ignore the noise. See how both stack up against the field in our best index funds by category, or run the numbers yourself with the expense ratio calculator.
Expense ratios and minimums drawn from fund provider documentation; last verified October 31, 2026. Editorial opinion, not investment advice. Confirm figures against the official prospectus before investing.