ITOT vs VTWNX: 21% overlap
iShares Core S&P Total U.S. Stock Market ETF and Vanguard Target Retirement 2020 share 20.6% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
Different holding dates. These holdings were published about 4 months apart — VTWNX as of 2026-03-31, the rest through 2026-07-23. Each fund is compared using its most recent file, so any trading in between shows up as a difference.
You would hold two tickers and get the diversification of 1.8. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
ITOT and VTWNX hold 2,386 of the same securities. The ten contributing most to the overlap figure:
| Holding | in ITOT | in VTWNX | Δ |
|---|---|---|---|
| NVDA | 7.0% | 1.3% | 5.8% |
| AAPL | 6.6% | 1.2% | 5.4% |
| MSFT | 3.9% | 0.8% | 3.2% |
| AMZN | 3.2% | 0.6% | 2.5% |
| GOOGL | 2.6% | 0.6% | 2.0% |
| AVGO | 2.6% | 0.5% | 2.1% |
| GOOG | 2.1% | 0.5% | 1.6% |
| MU | 1.6% | 0.4% | 1.2% |
| META | 1.8% | 0.3% | 1.5% |
| TSLA | 1.2% | 0.3% | 0.9% |
Where ITOT and VTWNX differ
Sector weights as a share of each fund, ordered by the size of the gap rather than the size of the sector — two funds that overlap heavily still usually diverge somewhere.
| Sector | ITOT | VTWNX | Δ |
|---|---|---|---|
| Unclassified | 0.0% | 29.8% | −29.8pp |
| Information Technology | 35.2% | 10.0% | +25.2pp |
| Treasuries | 0.0% | 17.1% | −17.1pp |
| MBS Pass-Through | 0.0% | 7.2% | −7.2pp |
| Health Care | 9.7% | 2.7% | +7.0pp |
| Communication Services | 8.7% | 2.3% | +6.4pp |
| Industrials | 10.1% | 4.0% | +6.1pp |
| Consumer Discretionary | 8.8% | 2.9% | +5.9pp |
Δ is ITOT minus VTWNX, in percentage points. Sector data is not published by every issuer, so “Unclassified” is a real category rather than a gap in the table.
What each fund holds alone
0.3% of ITOT by weight, held in no part of VTWNX.
77.3% of VTWNX by weight, held in no part of ITOT.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| ITOT | VTWNX | |
|---|---|---|
| Top 10 holdings | 32.7% | 44.9% |
| Positions held | 2,440 | 7 |
| Cost per $10,000 held, per year | $3 | $8 |
Cost is the expense ratio applied to $10,000; it excludes any brokerage commission, bid-ask spread or tax consequence. Figures are facts about the funds, not a suggestion about which to hold.
Frequently asked
How much do ITOT and VTWNX overlap?
ITOT and VTWNX overlap 20.6% by portfolio weight — moderate overlap. They share 2,386 holdings. The figure comes from current issuer holdings files (ITOT as of 2026-07-23, VTWNX as of 2026-03-31).
How is the overlap between ITOT and VTWNX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If ITOT holds a stock at 6% and VTWNX holds the same stock at 4%, 4% counts as shared. The result is bounded between 0% and 100%, and it is computed after looking through any fund-of-funds to the underlying holdings.
Is it redundant to hold both ITOT and VTWNX?
That depends on your goals — we state facts, not advice. At 20.6% overlap, each fund still contributes meaningfully distinct exposure.
What does ITOT own that VTWNX doesn't?
ITOT holds 2,440 positions and VTWNX holds 7; 53 of ITOT's positions don't appear in VTWNX at all, and they are 0.3% of ITOT by weight.
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Related comparisons
Sources: issuer holdings files, ITOT as of 2026-07-23, VTWNX as of 2026-03-31. Weights are fractions of each fund. Diagnostics, not advice.