VIMAX vs. FSMDX: Vanguard Mid-Cap Index Fund or Fidelity Mid Cap Index Fund?
Figures last verified October 31, 2026
Mid-cap index funds from Vanguard and Fidelity. The market's quiet overachiever segment, tracked by two near-identical low-cost funds.
| VIMAX | FSMDX | |
|---|---|---|
| Fund | Vanguard Mid-Cap Index Fund Admiral Shares | Fidelity Mid Cap Index Fund |
| Family | Vanguard | Fidelity |
| Category | Mid Cap | Mid Cap |
| Type | Index | Index |
| Expense ratio | 0.05% | 0.025% |
| Cost per $10k/yr | $5 | $2.50 |
| Minimum | $3,000 | $0 |
| Strategy | Tracks the CRSP US Mid Cap Index — about 300 middle-sized US companies. | Tracks the Russell Midcap Index — about 800 middle-sized US companies. |
FSMDX (0.025%, Russell Midcap, no minimum) is marginally cheaper than VIMAX (0.05%, CRSP Mid Cap, $3,000). Both do the one job cleanly. The index methodologies differ slightly but outcomes converge. Brokerage location is the deciding vote.
About VIMAX
Mid caps are the market's quiet overachievers: big enough to have survived the startup gauntlet, small enough to still double. Over long stretches, the segment has matched or beaten both its larger and smaller siblings with less drama than small caps. VIMAX captures it with characteristic Vanguard plainness — a few hundred companies, 0.05%, nothing to monitor.
About FSMDX
Mid caps rarely get their own headlines, which may be why they've quietly compounded so well — companies past the failure-prone startup phase but with room to grow that mega caps mathematically lack. FSMDX indexes roughly 800 of them via the Russell Midcap for 0.025%, no minimum, no manager.
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.