VTSAX vs FSKAX: Which Should You Pick?
VTSAX or FSKAX? Same market, 10-year returns 0.01 points apart, and a fee gap of $25 a year per $100k. Which to buy at each broker, and when not to switch.
VTSAX and FSKAX are the Vanguard and Fidelity versions of the same idea: one mutual fund that owns nearly every U.S. stock, weighted by market value. They track different indexes, the Morningstar US Total Market Index for VTSAX and the Dow Jones U.S. Total Stock Market Index for FSKAX, and over the ten years to June 30, 2026 they returned 15.03% and 15.04% a year. FSKAX charges 0.015% and VTSAX 0.04%, which is $25 a year on $100,000.
Quick answer
Buy whichever one your brokerage sells without a transaction fee: FSKAX at Fidelity, VTSAX (or the VTI ETF) at Vanguard. Do not sell an appreciated taxable position in one to buy the other. On a $100,000 holding with $40,000 of gains, a 20% combined tax rate costs $8,000 up front against $25 a year in fee savings. In IRAs and 401(k)s, where switching is tax-free, the lower fee is a fine tiebreaker. VTSAX has one structural edge in taxable accounts: at Vanguard it converts tax-free to the VTI ETF, which you can move to any broker.
| VTSAX | FSKAX | |
|---|---|---|
| Expense ratio | 0.04% | 0.015% |
| Minimum to open | $3,000 | $0 |
| Index | Morningstar US Total Market (formerly CRSP) | Dow Jones U.S. Total Stock Market |
| Holdings | 3,531 | 3,778 |
| Fund assets | $2.30 trillion (all share classes) | $138 billion |
| 10-year return (to 6/30/26) | 15.03% | 15.04% |
| 5-year return (to 6/30/26) | 12.23% | 12.26% |
| Turnover | 2.6% (2025) | 3% (FY ended Feb 2026) |
| Capital gains paid, last 10 fiscal years | None | Four years, none since FY2021 |
| Distributions | Income quarterly; any gains in December | April and December |
| ETF share class | Yes: VTI, tax-free one-way conversion at Vanguard | None |
Vanguard and Fidelity prospectuses (April 2026), fact sheets and annual reports. Holdings and returns as of June 30, 2026.
The two indexes produce the same portfolio
Both indexes weight every eligible U.S. stock by float-adjusted market value, so the largest companies dominate both funds in nearly the same proportions. The differences are in which micro-caps make the cut and when the index adds and drops names. Vanguard’s own prospectus shows the Dow Jones index returning 14.21% a year over the ten years to December 2025, against 14.25% for the index VTSAX tracks. Each fund also tracked its own index closely: within 0.02 percentage points a year over one, five and ten years.
The index name change at Vanguard is cosmetic. Morningstar bought CRSP and renamed its indexes, and on July 29, 2026 Vanguard renamed the fund the Vanguard Morningstar Total Stock Market Index Fund. Vanguard’s filing says the fund’s objective, strategies and policies did not change.
Taxes: both are efficient, VTSAX slightly more so
VTSAX has paid no capital gains distribution in any of the last ten years. It shares a portfolio with the VTI ETF, and the ETF’s in-kind redemptions let the fund shed low-basis shares without selling them. FSKAX has no ETF class. It paid capital gains in fiscal years 2017 through 2020, from $0.13 to $0.51 a share, and none in the six fiscal years since. Over the ten years to 2025, the funds’ published after-tax returns on distributions were 13.78% for VTSAX and 13.75% for FSKAX, so the difference was 0.03 points a year in that window. In a taxable account that is a small edge for VTSAX; in an IRA or 401(k) it does not apply.
Portability decides more than the fee
At Vanguard, VTSAX shares convert to VTI without a taxable sale. Vanguard notes that conversions are tax-free when both share classes are held there, and they run one way only. VTI can then move in kind to any brokerage. FSKAX has no equivalent route. If you might leave Fidelity, check before you transfer whether the new broker will hold FSKAX and what it charges to buy more. The reverse holds too: Fidelity lists a $100 online transaction fee on each VTSAX purchase, so adding to VTSAX at a Fidelity account costs more in a single trade than several years of the fee gap.
FSKAX is a different case from FZROX, Fidelity’s zero-fee fund, which follows a proprietary index of about 2,700 stocks and can only be held in a Fidelity account. FSKAX tracks an outside index with more holdings than VTSAX, and for investors who expect to stay at Fidelity it is the cleaner choice of the two Fidelity funds.
Switching an existing position
In a tax-advantaged account, switching costs nothing and the fee gap is $25 a year per $100,000. In a taxable account, the tax on embedded gains usually outweighs decades of fee savings. Enter your own position below; the defaults are set for a VTSAX holder considering FSKAX. Our guide to switching to a cheaper index fund works through the after-tax math and the cases where a switch pays.
Using one as a tax-loss harvesting partner
Because the two funds track different indexes from different managers, investors often harvest a loss in one and buy the other. IRS Publication 550 says only that whether securities are substantially identical depends on “all the facts and circumstances,” and it does not address index funds. No IRS ruling covers this pair, so the question is unsettled. Our tax-loss harvesting guide covers how to choose partners and the wash-sale rule’s 30-day windows.
Who should pick which
Pick VTSAX if you
- Invest at Vanguard and want automatic dollar-amount purchases.
- Hold it in a taxable account and value the tax-free route to VTI.
- Already own it with gains; keep it.
Pick FSKAX if you
- Invest at Fidelity, where it trades without a fee or minimum.
- Want a total-market fund in a Fidelity IRA or 401(k).
- Prefer an outside index to FZROX’s proprietary one.
Sources and related reading
- Vanguard Total Stock Market Index Fund summary prospectus (April 28, 2026), July 29, 2026 supplement on the Morningstar rename, and annual report for 2025.
- Fidelity Total Market Index Fund summary prospectus (April 29, 2026) and annual report for the year ended February 28, 2026.
- Vanguard, converting mutual fund shares to ETF shares; Fidelity’s VTSAX research page (transaction fee, read October 2026) ; IRS Publication 550.
- VTI vs VTSAX, FZROX vs VTSAX, VTI vs ITOT, FSKAX vs FZROX, and why Fidelity’s ZERO funds optimize the wrong variable.
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