Fidelity’s ZERO funds charge a literal 0.00% expense ratio, while Vanguard’s comparable index funds charge 0.03–0.04%. On the surface, that makes the choice look obvious. In practice, the two fund families differ in ways that matter more than the headline fee — proprietary indexes, portability, and even how dividends get reinvested.
Quick Verdict
| Category | Winner |
|---|---|
| Lowest headline expense ratio | Fidelity ZERO (FZROX, FZILX, FNILX, FZIPX at 0.00%) |
| Best if you might ever switch brokers | Vanguard (ETFs transfer in-kind everywhere) |
| Longer track record and larger asset base | Vanguard (VTSAX, decades of history) |
| Best for a Fidelity-only, buy-and-hold investor | Fidelity ZERO |
| Better in a taxable account | Vanguard (fund structure minimizes capital gains distributions) |
The Head-to-Head: FZROX vs. VTSAX
| Fund | Provider | Expense ratio | Index tracked | Vehicle type |
|---|---|---|---|---|
| FZROX | Fidelity | 0.00% | Fidelity U.S. Total Investable Market Index (proprietary) | Mutual fund |
| VTSAX | Vanguard | 0.04% | CRSP US Total Market Index | Mutual fund |
| VTI | Vanguard | 0.03% | CRSP US Total Market Index | ETF |
| FSKAX | Fidelity | 0.015% | Dow Jones U.S. Total Stock Market Index | Mutual fund |
On a $100,000 portfolio, the dollar difference between FZROX (0.00%) and VTI (0.03%) is about $30 a year — real, but modest. Historical returns between the two have tracked each other closely enough that independent fund-comparison sites report a near-perfect 0.99–1.00 correlation between them; over the past five years, one has occasionally edged out the other by a fraction of a percentage point, but there’s no consistent, predictable winner.
The Detail Most Comparisons Miss: Different Indexes
FZROX doesn’t track the same index as VTSAX. Fidelity’s ZERO funds follow Fidelity’s own proprietary index, while VTSAX tracks the CRSP US Total Market Index and FSKAX tracks the Dow Jones U.S. Total Stock Market Index. These indexes are constructed differently and hold a slightly different number of underlying stocks, which is the actual source of the small performance gap between the funds — not the expense ratio itself. Over any given short period, this can make either fund look like the “winner,” but it isn’t a fee effect; it’s a difference in what’s being measured.
A Subtler Cost: Dividend Reinvestment Timing
One frequently overlooked factor is how each fund handles dividends. Vanguard’s fund structure allows even its mutual fund share classes (VTSAX) to reinvest dividends more frequently and share a structure with the ETF version that helps minimize taxable capital gains distributions. Some independent analyses have found that FZROX’s slower dividend reinvestment schedule, compounded over long periods, can offset some or all of its expense ratio advantage — one widely cited long-run simulation estimated the gap at roughly 2–3% over a 40-year holding period, working in Vanguard’s favor. This effect is specific to taxable accounts holding dividend-paying total market funds over very long horizons; it has no bearing on a Roth IRA or 401(k), where dividends are automatically tax-advantaged regardless of reinvestment timing.
The Real Dealbreaker: Portability
This is the factor that should carry the most weight for most people. FZROX and the rest of Fidelity’s ZERO lineup are proprietary mutual funds available exclusively through a Fidelity brokerage account. If you ever want to move to Schwab, Vanguard, or any other broker, you cannot transfer these funds in-kind — you have to sell them first. In a tax-advantaged account (Roth IRA, 401(k)), that’s a non-event. In a taxable brokerage account, selling triggers a capital gains tax event, which can meaningfully complicate an otherwise simple broker switch.
Vanguard’s VTI, by contrast, is an ETF and transfers to literally any brokerage without being sold. If there’s a realistic chance you’ll change brokers in the future — say, for a better cash sweep rate or a feature you want elsewhere — that portability is worth more than the few basis points FZROX saves.
Which One Should You Choose?
If you’re confident you’ll stay at Fidelity long-term and you’re investing inside a Roth IRA or 401(k) where the tax-drag and portability concerns don’t apply, FZROX’s 0.00% expense ratio is a genuinely good deal with essentially no downside. If you’re investing in a taxable account, might switch brokers someday, or simply prefer the long track record and investor-owned structure behind Vanguard’s funds, VTI or VTSAX remain excellent choices even at a marginally higher fee. For most investors, this comparison comes down to a preference and a portability judgment call rather than a real difference in expected returns.
Disclosure: This article is for educational purposes only and does not constitute financial or investment advice. We are not licensed financial advisors. Expense ratios and fund data reflect publicly available information as of 2026 and are subject to change — verify current figures directly with each fund provider before investing. Some links on this page may be affiliate links.
Last reviewed: July 2026.