FSKAX vs FZROX: Fidelity Total Market Funds Compared (2026)
Fidelity offers two excellent total U.S. stock market index funds: FSKAX at 0.015%, and FZROX at literally 0.00%. Free sounds great — but FZROX comes with some important limitations you need to know before investing.
⚠️ The Portability Trap
FZROX cannot be transferred to another brokerage. If you ever switch from Fidelity, you'll need to sell your FZROX shares — potentially triggering capital gains taxes. FSKAX does not have this restriction.
FSKAX vs FZROX: At a Glance
| Metric | FSKAX | FZROX |
|---|---|---|
| Expense Ratio | 0.015% | 0.00% |
| Annual Cost on $10,000 | $1.50 | $0.00 |
| Minimum Investment | $0 (both) | |
| Index Tracked | Dow Jones U.S. Total Stock Market | Fidelity U.S. Total Investable Market (proprietary) |
| Number of Holdings | ~3,900 | ~2,700 |
| Portable to Other Brokerages? | Yes | No |
| Tax Efficiency (Taxable) | Slightly better | Good |
| Correlation | 0.99 (near-perfect) | |
Historical Returns: FSKAX vs FZROX
Performance between FSKAX and FZROX is nearly identical — both funds track the total U.S. stock market and move in near-perfect lockstep (correlation of ~0.99).
| Time Period | FSKAX | FZROX |
|---|---|---|
| 1-Year Return | ~8% | ~8% |
| 3-Year Annualized | ~8.5% | ~8.5% |
| 5-Year Annualized | ~16% | ~15.9% |
FZROX launched in 2018, so long-term data is limited. Based on available history, returns are functionally identical. Don't choose between these two funds based on performance.
The Portability Problem with FZROX
This is the biggest practical difference. FZROX is exclusively a Fidelity fund and cannot be transferred to another brokerage. If you ever want to move your investments, you would need to sell your FZROX shares before moving — triggering capital gains taxes in a taxable account.
FSKAX, by contrast, tracks the standard Dow Jones U.S. Total Stock Market Index and can be transferred to other brokerages, held in 401(k)s, and is generally more flexible.
FSKAX vs FZROX: Which Should You Choose?
Choose FSKAX if you…
- ✅ Might switch brokerages someday (portability matters)
- ✅ Are investing in a taxable account (better tax efficiency)
- ✅ Prefer a well-known, established benchmark index
- ✅ Want broader market coverage (~3,900 stocks)
Choose FZROX if you…
- ✅ Are confident you'll stay at Fidelity long-term
- ✅ Investing in a Roth IRA, IRA, or 401(k)
- ✅ Want to pay absolutely nothing in fund fees
Our take: For taxable accounts, FSKAX is the safer choice. For tax-advantaged accounts where you're committed to Fidelity, FZROX's zero expense ratio is a genuine (if small) advantage.
Frequently Asked Questions
What is the difference between FSKAX and FZROX?
Both are Fidelity total U.S. stock market funds with $0 minimums. FZROX charges 0.00% but tracks a proprietary Fidelity index, holds fewer stocks (~2,700 vs ~3,900), and cannot be transferred to other brokerages. FSKAX charges 0.015%, tracks the standard Dow Jones index, and is fully portable.
Is FZROX really free? What's the catch?
FZROX genuinely charges 0.00% per year. The main catch is that it can only be held at Fidelity — you can't transfer it to another brokerage. Also, it tracks a proprietary index rather than a standard benchmark.
Which is better for a Roth IRA: FSKAX or FZROX?
FZROX is a strong choice for a Roth IRA if you plan to stay at Fidelity. The zero expense ratio is a real benefit over time. FSKAX is better if you think you might move your IRA.
Can I transfer FZROX to another brokerage?
No. FZROX is Fidelity-exclusive and cannot be transferred in-kind. You'd need to sell it first, potentially triggering capital gains taxes in a taxable account.
Does FZROX hold fewer stocks than FSKAX?
Yes — FZROX holds ~2,700 stocks vs FSKAX's ~3,900. The additional 1,200 stocks in FSKAX are micro-caps that collectively represent less than 1% of fund value.
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