FSKAX Review 2026

By WealthIQ Editorial  |  Last Updated: March 2026

Fidelity’s total market index fund charges nothing — literally $0 in annual fees. That makes FSKAX one of the few funds where the long-term math is almost impossible to argue with. Here’s what the data shows about how it performs against comparable funds.

What Is FSKAX?

FSKAX — the Fidelity Total Market our VOO ETF review — is a mutual fund that tracks the Dow Jones U.S. Total Stock Market Index. Unlike the S&P 500, which covers 500 large-cap companies, FSKAX holds over 2,700 stocks spanning large-cap, mid-cap, small-cap, and micro-cap U.S. equities. If a company is listed on a U.S. exchange and meets basic liquidity requirements, there’s a good chance it’s in FSKAX.

Launched in 2011, FSKAX has grown into one of Fidelity’s flagship index products. Its expense ratio sits at just 0.015% — so low it’s effectively free. On a $10,000 investment, you’d pay about $1.50 per year in fees. Compare that to the average actively managed fund charging 0.5–1.0%, and the math becomes obvious.

FSKAX vs. FXAIX review: Total Market vs. S&P 500

This is the most common comparison Fidelity investors face. FXAIX is Fidelity’s S&P 500 index fund — 500 large-cap companies only. FSKAX covers the whole market.

In practice, the two funds behave similarly. Large-cap stocks (the S&P 500 universe) account for roughly 82–85% of FSKAX’s weight. So adding mid- and small-cap exposure through FSKAX only modestly changes your portfolio’s character.

That said, small-cap stocks have historically offered a return premium over long periods — though with more volatility. If you believe in broad diversification and want to capture every corner of the U.S. market, FSKAX is the better choice. If you only want exposure to large-cap blue chips, FXAIX is fine.

FSKAX vs. VTI: Which Total Market Fund Wins?

VTI (Vanguard Total Stock Market ETF) is FSKAX’s closest competitor — both track the total U.S. market, both carry minimal fees, and both have delivered virtually identical long-term returns. The key differences are structural:

• FSKAX is a mutual fund. You buy it at end-of-day NAV. VTI is an ETF that trades intraday like a stock.
• FSKAX has no minimum. VTI requires buying at least one share (currently ~$270). FSKAX lets you invest any dollar amount.
• FSKAX is Fidelity-only. VTI is available at any brokerage.
• VTI’s expense ratio is 0.03% — slightly higher than FSKAX’s 0.015%, though the difference is negligible.

Comparison Table: FSKAX vs. VTI vs. FXAIX

*Approximate annualized returns as of early 2026. Past performance does not guarantee future results.

Who Should Use FSKAX?

FSKAX makes sense if you:

• Already use Fidelity as your primary brokerage or IRA custodian
• Want total U.S. market exposure in a single fund
• Prefer mutual fund mechanics — automatic investing, fractional shares by dollar amount, no bid/ask spread
• Are a long-term, passive investor who doesn’t need intraday trading

FSKAX is less ideal if you invest at Vanguard, Schwab, or another brokerage — in that case, VTI or SWTSX would be more accessible options.

How FSKAX Fits Into a Portfolio

For most investors, FSKAX can serve as a core holding — the anchor of your equity allocation. A simple three-fund portfolio might pair FSKAX with an international index fund (like FZILX) and a bond fund (like FXNAX). This gives you diversified global exposure at near-zero cost.

If you’re investing in a Fidelity 401(k) or IRA, FSKAX is often one of the best options available. Check your plan’s fund lineup — you may find it listed as the “U.S. Stock Market Index” option.

What Works, What Doesn’t

Pros:

• Virtually zero cost (0.015% expense ratio)
• Broad U.S. market exposure — 2,700+ stocks
• No investment minimum — invest any dollar amount
• Automatic dividend reinvestment
• Tax-efficient structure for taxable accounts

Cons:

• Only available at Fidelity — no portability to other brokers
• Mutual fund NAV pricing — no intraday trading
• Slightly higher small-cap weight means marginally more volatility vs. FXAIX

Bottom Line

FSKAX is an excellent fund for anyone building long-term wealth at Fidelity. Its near-zero fee, broad diversification, and dollar-based investing make it one of the best mutual funds available — period. If you’re a Fidelity investor who wants simple, total U.S. market exposure without thinking twice about fees, FSKAX belongs in your portfolio.