FXAIX costs more than you'd expect for a total market index fund

FXAIX (Fidelity Total Market Index Fund) has an expense ratio of 0.03%, which is low by most standards but higher than Fidelity's own competing index fund, SWTSX, which costs 0.04%. The difference seems small until you run the math over decades. On a $100,000 investment, you'd pay $30 per year with FXAIX versus $40 with SWTSX — so FXAIX is actually cheaper. The real comparison that confuses people is FXAIX versus Vanguard's VTSAX (0.04%) or Schwab's SWTSX (0.04%), where FXAIX wins by a hair.

The reason FXAIX's ratio seems high relative to what you might expect is historical. Fidelity launched FXAIX in 2011 as a mutual fund version of its index strategy, and mutual funds carry slightly higher costs than exchange-traded funds (ETFs) because of how they're structured and traded. Fidelity has since lowered the ratio multiple times, but it remains fractionally above some competitors' offerings.

Key Takeaways

  • FXAIX's 0.03% expense ratio is genuinely low and costs less than most competing total market index funds in absolute dollars.
  • The fund tracks the entire U.S. stock market (about 3,500 companies) and holds the same securities as its competitors, so performance differences are minimal.
  • Mutual fund structure (FXAIX is a mutual fund, not an ETF) adds a small layer of cost that ETF competitors avoid, but the difference is negligible for most investors.
  • Fidelity has cut FXAIX's expense ratio repeatedly over the past decade, showing the company competes on cost even within its own product line.

How FXAIX's structure affects its cost

FXAIX is a mutual fund, not an exchange-traded fund (ETF). That distinction matters for expenses. Mutual funds are priced once per day after the market closes, and they're bought and sold directly through the fund company. ETFs trade throughout the day on an exchange like stocks do. The daily pricing and direct-sale model for mutual funds requires more administrative overhead, which shows up in the expense ratio.

Fidelity's ETF version of the same strategy, FSKAX, costs the same 0.03%. So if you own FXAIX in a regular brokerage account (not a retirement account), you could switch to FSKAX and pay identical fees while gaining the ability to trade intraday and use limit orders. In a 401(k) or IRA, your plan administrator chooses which version is available, so you may not have that option.

Why the ratio hasn't dropped below 0.03%

Fidelity could theoretically lower FXAIX's expense ratio further, but 0.03% is already at the floor of what's economically viable for a mutual fund. Below that point, the fund company loses money on every transaction. Fidelity's business model relies on keeping customers in its ecosystem — they make money on trading commissions, advisory fees, and 401(k) administration, not on squeezing the last basis point out of index funds.

Vanguard and Schwab can offer 0.04% ratios partly because they're structured differently (Vanguard is investor-owned, Schwab bundles index funds with brokerage services) and partly because they're willing to operate index funds at razor-thin margins as a way to retain customers. Fidelity's 0.03% is competitive enough that most investors won't notice the difference, and the company has chosen to hold it there rather than race to zero.

How much FXAIX's expense ratio actually costs you

The real test of whether FXAIX is expensive is what you pay in dollars, not what the ratio number looks like. On a $50,000 position, 0.03% costs $15 per year. On $500,000, it's $150 per year. On $1 million, it's $300 per year. If you're comparing FXAIX to VTSAX (Vanguard's equivalent at 0.04%), the difference on $500,000 is $50 per year — less than the cost of a single trading commission on most platforms.

The expense ratio compounds over time, so a 0.01% difference does matter across 30 years. But the difference between FXAIX and its closest competitors is so small that other factors — whether the fund is available in your 401(k), whether you already have a Fidelity account, whether you prefer Fidelity's interface — will affect your total return far more than the expense ratio will.

When FXAIX makes sense despite the ratio

FXAIX is the right choice if you have a Fidelity 401(k) or IRA and it's one of the index fund options available to you. Fidelity's retirement accounts don't charge transaction fees for buying their own funds, so you can rebalance without cost. If you're building a portfolio in a Fidelity brokerage account, FXAIX and FSKAX (the ETF version) are equally cheap, so pick whichever trading style suits you.

FXAIX is also reasonable if you're already using Fidelity for other accounts and want to keep everything in one place. The convenience of a single login and consolidated statements is worth more than 0.01% per year to most people. If you're choosing between Fidelity and another brokerage solely on the basis of index fund expense ratios, the difference is too small to matter.

Frequently Asked Questions

Is FXAIX cheaper than VTSAX or SWTSX?

FXAIX costs 0.03% per year. VTSAX (Vanguard) and SWTSX (Schwab) both cost 0.04%. On a $500,000 investment, that's a $50 annual difference in your favor with FXAIX. The difference is real but small enough that account features and convenience usually matter more.

Should I switch from FXAIX to a cheaper fund?

Only if you're moving to a different brokerage anyway. The cost of selling FXAIX and buying a competitor's fund (in taxable accounts, this triggers capital gains tax) will wipe out years of savings from a lower expense ratio. In a retirement account with no tax consequence, the decision depends on whether the new brokerage offers better features or lower costs elsewhere.

Why does Fidelity have both FXAIX and FSKAX if they cost the same?

FXAIX is a mutual fund; FSKAX is an ETF. They track the same index and cost the same, but ETFs trade throughout the day like stocks, while mutual funds price once daily. Choose based on how you want to trade, not on cost.

Will FXAIX's expense ratio go lower?

Unlikely. At 0.03%, Fidelity is already operating at the margin of profitability for a mutual fund. Further cuts would require restructuring the fund as an ETF or changing how Fidelity's business model works. The ratio has stayed stable for several years, suggesting Fidelity sees 0.03% as its target.