VTI and ITOT are the two heavyweight total US stock market ETFs in 2026. Combined assets cross roughly $500 billion. They both promise the same thing: own the entire investable US equity market in one ticker, at a fee low enough that you basically forget about it. They deliver on that promise in nearly identical ways — and the differences between them are smaller than most online comparisons suggest.
This article walks through the actual numbers: benchmark methodology (CRSP US Total Market vs S&P Total Market), expense ratios, ten-year total returns, holdings overlap, tracking difference relative to benchmark, AUM, and the one scenario where holding both makes sense (tax-loss harvesting). All figures sourced from Vanguard, iShares, and Morningstar as of early 2026. For the closely related single-fund-vs-S&P-500 question, see our companion VTI vs VOO 2026 comparison.
The Headline Numbers (Early 2026)
| Metric | VTI | ITOT |
|---|---|---|
| Expense ratio | 0.03% | 0.03% |
| AUM (approx.) | $440B | $65B |
| Holdings (approx.) | ~3,600 | ~2,800 |
| 30-day SEC yield | ~1.30% | ~1.30% |
| Benchmark | CRSP US Total Market | S&P Total Market |
| Inception | May 2001 | Jan 2004 |
| Trailing 10-yr return (approx.) | ~12.3% | ~12.3% |
| Tracking diff. vs. benchmark | ~1–3 bps | ~2–4 bps |
| Issuer | Vanguard | iShares (BlackRock) |
Figures are approximate, as of early 2026, sourced from Vanguard's VTI fund page, iShares's ITOT fund page, and Morningstar. AUM moves daily; expense ratios and structural details are stable.
The Benchmark Difference: CRSP vs S&P Total Market
This is the single structural difference between the two funds. VTI tracks the CRSP US Total Market Index. ITOT tracks the S&P Total Market Index. Both target roughly 99.5% of the investable US equity market by full-float market capitalization. Both are market-cap-weighted. Both have minimal turnover. The differences are in inclusion rules and reconstitution methodology:
- Coverage breadth: CRSP includes roughly 3,600 stocks; S&P Total Market includes roughly 2,500–3,000. The difference lives in the micro-cap tail. CRSP is more inclusive of newly listed names, recent spinoffs, and small-float companies that S&P excludes via stricter liquidity and float-adjusted market cap screens.
- Inclusion rules: S&P Total Market applies S&P Dow Jones Indices' profitability and liquidity screens (similar to but looser than the S&P 500's GAAP-profitability rule). CRSP applies broader rules from the Center for Research in Security Prices at the University of Chicago — closer to a pure cap-weighted census of US-listed equities.
- Reconstitution: CRSP uses a packetized reconstitution model that smooths buffer-zone transitions to reduce index-fund trading costs. S&P Total Market reconstitutes on a more conventional schedule with sharper buffer zones, which can produce slightly more transaction cost drag.
The combined effect of these differences shows up as a roughly 1–2 basis point per year structural performance gap, which is well within tracking noise. Over the trailing 10 years ending early 2026, both ETFs have returned approximately 12.3% annualized on a total return basis — effectively a dead heat. The CRSP edge in some windows is offset by the S&P edge in others, and the long-run difference is too small to base a fund selection on.
Expense Ratio: Tied at 0.03%
Both VTI and ITOT charge 0.03% annually — $3 per year per $10,000 invested. This is the same expense ratio as VOO, IVV, SPY (well, SPY charges 0.0945%), and most of the major mega-cap-weighted US equity ETFs. iShares lowered ITOT's expense ratio from 0.07% to 0.03% in 2019 to match Vanguard's VTI in the long-running fee race-to-zero. Both products are at the realistic floor for a $50B+ AUM total market ETF in 2026.
For investors who want to push expense ratio below 0.03%, the alternatives are mutual-fund-only products: FZROX (Fidelity ZERO Total Market Index Fund) at 0.00%, FSKAX (Fidelity Total Market Index Fund) at 0.015%, SWTSX (Schwab Total Stock Market Index Fund) at 0.03%. None of these are ETFs; all have portability limitations to their issuing brokerages. If you want one-ticker total market exposure that travels across all major brokerages without restriction, VTI and ITOT are the two products that matter.
Returns: A Statistical Dead Heat
Over every meaningful trailing window — 1-year, 3-year, 5-year, 10-year — VTI and ITOT have returned within 5–10 basis points per year of each other. The small differences in any given window are mostly explained by:
- The CRSP vs S&P Total Market sampling difference in mid- and micro-caps (typically 1–3 bps/year).
- Cash drag differences (typically <1 bp/year).
- Reconstitution transaction cost differences (typically 1–2 bps/year).
| Period | VTI (approx.) | ITOT (approx.) | Gap |
|---|---|---|---|
| 1-year | ~17.0% | ~16.95% | +5 bps |
| 3-year annualized | ~10.0% | ~10.0% | ≈0 |
| 5-year annualized | ~13.0% | ~12.95% | +5 bps |
| 10-year annualized | ~12.3% | ~12.3% | ≈0 |
Returns approximated from Morningstar total return data as of early 2026. The 10-year returns are effectively identical — the funds have been tracking each other very closely over the relevant window. If you are looking at this comparison to pick the “higher-returning” fund, you are looking at the wrong differentiator.
Tracking Difference: Both Near-Perfect
Tracking difference is the gap between a fund's net-of-fee total return and the gross total return of its benchmark. Vanguard reports VTI tracking the CRSP US Total Market Index with a 1–3 basis point annual difference. iShares reports ITOT tracking the S&P Total Market Index with a 2–4 basis point annual difference. ITOT's slightly wider band reflects the higher transaction cost drag from S&P Total Market's less smoothed reconstitution.
Both numbers are excellent — at or near the realistic floor for a passively managed total market ETF. The 1–3 bp difference between VTI and ITOT tracking errors is not visible in any practical portfolio simulation. Treat them as equally well-tracked.
Holdings Overlap: 97–98% on a Weight Basis
Both ETFs are market-cap-weighted total market indexes, so they converge at the top. The top 100 holdings of VTI and ITOT are essentially identical with nearly identical weights. The portfolio-weight overlap is approximately 97–98%. The 2–3% difference lives in the small- and micro-cap tail.
Top 10 holdings (early 2026, both ETFs): Microsoft, Apple, Nvidia, Alphabet, Amazon, Meta, Berkshire Hathaway, Eli Lilly, Broadcom, JPMorgan. Top 10 represents roughly 28% of each portfolio. The next 90 names represent roughly an additional 32%, and the long tail of ~2,500–3,500 names represents the remaining ~40%.
If you want to dig into how this concentration compares to a pure S&P 500 holding, our VTI vs VOO comparison walks through the small- and mid-cap tail differential in detail — the same logic applies to VTI vs VOO and ITOT vs IVV.
Tax-Loss Harvesting: The One Reason to Own Both
The legitimate use case for holding both VTI and ITOT is tax-loss harvesting in a taxable account. The IRS wash-sale rule prohibits you from claiming a loss if you buy a “substantially identical” security within 30 days before or after the sale. Two ETFs that track different indexes (CRSP US Total Market vs S&P Total Market) and are issued by different sponsors (Vanguard vs iShares) are generally considered not substantially identical under prevailing IRS interpretation.
The practical workflow:
- Hold VTI in taxable account. Market drops 10–15%.
- Sell VTI, realizing a capital loss that can offset capital gains (or up to $3,000 of ordinary income per year, with the rest carried forward).
- Immediately buy ITOT with the proceeds. You maintain US total market exposure with no out-of-market gap.
- Wait 31+ days. Optionally swap back to VTI if you prefer.
This strategy works in either direction (ITOT → VTI is equally valid). It can produce meaningful tax savings during market drawdowns. Note that the “not substantially identical” status is IRS interpretation, not statute — extremely conservative tax advisors sometimes argue VTI and ITOT are close enough to risk a challenge. Most practitioners treat the pair as safe for harvesting. Consult your CPA if your taxable account is large enough that the harvesting savings would be material.
AUM and Liquidity
VTI is roughly seven times larger than ITOT by AUM in early 2026 — approximately $440B vs $65B. Both have ample daily trading volume and tight bid-ask spreads (typically 1 cent on retail-size orders). For retail investors, the liquidity difference is irrelevant. For institutional-scale orders (millions of shares), VTI's deeper book provides a small execution advantage. For 99% of personal investors, both are perfectly liquid.
When to Pick VTI
- You hold a Vanguard brokerage account and want commission-free trading on the issuer's flagship total market ETF.
- You prefer Vanguard's mutual-ownership corporate structure on ideological grounds.
- You want the slightly broader micro-cap coverage of the CRSP index.
- You are starting a new position in a vanilla three-fund or two-fund portfolio (VTI + VXUS + BND, or VTI + VXUS).
When to Pick ITOT
- You hold a Fidelity, Merrill Edge, or Schwab account where ITOT is the preferred commission-free iShares total market ETF.
- You want to use ITOT as the partner fund in a VTI tax-loss harvesting pair.
- You prefer the slightly tighter S&P Total Market inclusion screens (excludes the lowest-quality micro caps).
- You hold other iShares ETFs (IXUS, AGG) and want issuer consistency across your portfolio.
The Bottom Line
VTI and ITOT are functionally interchangeable. Both deliver the entire US equity market at 0.03% with 1–3 bp tracking error and essentially identical 10-year returns. The methodological differences between CRSP and S&P Total Market are real but their portfolio-return impact is too small to drive a fund selection on its own.
Pick whichever your primary brokerage prefers and stop optimizing. If you find yourself in a market drawdown holding one of them in a taxable account, harvest the loss and buy the other — that's the highest-value reason to keep the pair on your radar.
For the related question of whether to own a total market ETF or a pure S&P 500 fund, see VTI vs VOO 2026. For the ETF-vs-mutual-fund tax structure question that drives both decisions, see ETF vs Mutual Funds 2026. And once you have your domestic core sorted, the next question is usually international: a sibling piece on VXUS vs IXUS is the natural follow-on. Across-site, the cost-of-living math behind picking your overall allocation lives at our cost of living comparison calculator — useful when modeling savings rate by city.
Frequently Asked Questions
Is VTI or ITOT a better total US stock market ETF in 2026?
Both are functionally interchangeable. VTI (Vanguard) holds roughly 3,600 US stocks tracking the CRSP US Total Market Index; ITOT (iShares) holds roughly 2,500–3,000 stocks tracking the S&P Total Market Index. Expense ratios are nearly identical (VTI 0.03%, ITOT 0.03%). Performance over the trailing 10 years has been within 5–10 basis points per year, almost entirely explained by mid- and small-cap sampling differences between the two benchmarks. Pick VTI if you are already in the Vanguard ecosystem and want one-ticker simplicity; pick ITOT if you are inside a Fidelity/Merrill/Schwab account where ITOT is a commission-free preferred fund. The structural bet — full US market exposure — is the same.
What is the difference between the CRSP and S&P Total Market indexes?
CRSP US Total Market Index (VTI's benchmark) targets roughly 99.5% of the investable US equity market by full-float market cap, using packetized reconstitution that smooths buffer-zone churn. S&P Total Market Index (ITOT's benchmark) targets the same 99.5% but uses S&P Dow Jones Indices' classification rules, which include slightly stricter profitability and liquidity screens for inclusion of micro-cap names. The practical result: CRSP has roughly 3,600 names while S&P Total Market has roughly 2,500–3,000 names. Both indexes have been within ~5 basis points of each other on total return for the past decade. The methodological difference is real but its return impact is small.
How much do VTI and ITOT overlap in holdings?
The top 100 holdings of VTI and ITOT are essentially identical with nearly identical weights — both are market-cap weighted total market indexes, so they converge at the top. The overlap on a portfolio-weight basis is approximately 97–98%. The 2–3% difference lives in the small- and micro-cap tail where CRSP includes names that the S&P Total Market screens exclude (typically newly listed companies, recently spun-off entities, or micro caps below S&P's liquidity threshold). Both top out at Microsoft, Apple, Nvidia, Alphabet, Amazon, Meta, Berkshire Hathaway, and the same handful of mega caps.
Are VTI and ITOT equally tax-efficient?
Both have an outstanding capital gains distribution track record. VTI has historically benefited from Vanguard's patented dual-share-class structure (which expired in 2023 but continues to confer some tax-efficiency advantages through embedded basis). ITOT benefits from iShares' use of heartbeat trades and in-kind creation/redemption mechanics, which are the standard ETF tax-efficiency tools available to all ETFs. Both have distributed zero or near-zero capital gains in most years of the past decade. For taxable accounts, the tax difference between VTI and ITOT is essentially irrelevant — both are best-in-class.
What is the tracking difference for VTI vs ITOT?
Both ETFs post tracking differences in the 1–3 basis point range annually relative to their stated benchmarks. iShares ITOT has historically run at ~2–4 basis points behind the S&P Total Market Index; Vanguard VTI has run at ~1–3 basis points behind the CRSP US Total Market Index. The slightly wider ITOT tracking difference reflects S&P Total Market's larger reconstitution buffer churn, which produces more transaction cost drag than CRSP's packetized methodology. Both numbers are excellent and competitive with the broader category.
Should I own both VTI and ITOT for diversification?
No. Owning both is double-counting — you would hold the same companies twice with no meaningful diversification benefit. The two ETFs are substitutes, not complements. Pick one and stick with it. The only legitimate reason to hold both is tax-loss harvesting: if you sell ITOT at a loss in a taxable account, you can immediately buy VTI and maintain US total market exposure without triggering the wash-sale rule, because they track different indexes (CRSP vs S&P) and are not 'substantially identical' under IRS interpretation.
Which is better in a taxable account: VTI or ITOT?
Either works. The decision often comes down to brokerage commissions and platform preferences rather than fund characteristics. If you use Fidelity, ITOT trades commission-free and pairs naturally with Fidelity's iShares partnership. If you use Vanguard, VTI is the default. If you use Schwab, both are commission-free but SCHB (Schwab's competing total market ETF, 0.03% expense ratio) is often preferred for the same reason. The relevant tax-efficiency questions are identical for VTI and ITOT: both have ETF structure benefits, both have low turnover, both have near-zero capital gains distribution history.