ITOT vs IWM: 4% overlap
iShares Core S&P Total U.S. Stock Market ETF and iShares Russell 2000 ETF share 4.3% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
You would hold two tickers and get the diversification of 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
ITOT and IWM hold 1,396 of the same securities. The ten contributing most to the overlap figure:
| Holding | in ITOT | in IWM | Δ |
|---|---|---|---|
| CASH | 0.2% | 0.2% | 0.0% |
| HUT | 0.0% | 0.4% | 0.4% |
| MOG-A | 0.0% | 0.4% | 0.4% |
| CYTK | 0.0% | 0.3% | 0.3% |
| BTSG | 0.0% | 0.4% | 0.3% |
| CTRE | 0.0% | 0.3% | 0.3% |
| VSAT | 0.0% | 0.3% | 0.3% |
| UMBF | 0.0% | 0.3% | 0.3% |
| CRNX | 0.0% | 0.3% | 0.3% |
| ONB | 0.0% | 0.3% | 0.3% |
Where ITOT and IWM 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 | IWM | Δ |
|---|---|---|---|
| Information Technology | 35.2% | 12.8% | +22.3pp |
| Health Care | 9.7% | 19.9% | −10.2pp |
| Financials | 12.7% | 19.0% | −6.4pp |
| Communication Services | 8.7% | 2.5% | +6.2pp |
| Industrials | 10.1% | 14.7% | −4.5pp |
| Real Estate | 2.3% | 5.9% | −3.6pp |
| Energy | 3.5% | 6.1% | −2.6pp |
| Consumer Staples | 4.4% | 2.2% | +2.3pp |
Δ is ITOT minus IWM, 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
95.6% of ITOT by weight, held in no part of IWM.
7.4% of IWM 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 | IWM | |
|---|---|---|
| Top 10 holdings | 32.7% | 3.3% |
| Positions held | 2,440 | 1,967 |
| Cost per $10,000 held, per year | $3 | $19 |
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 IWM overlap?
ITOT and IWM overlap 4.3% by portfolio weight — largely distinct portfolios. They share 1,396 holdings. The figure comes from current issuer holdings files (ITOT as of 2026-07-23, IWM as of 2026-07-23).
How is the overlap between ITOT and IWM 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 IWM 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 IWM?
That depends on your goals — we state facts, not advice. At 4.3% overlap, each fund still contributes meaningfully distinct exposure.
What does ITOT own that IWM doesn't?
ITOT holds 2,440 positions and IWM holds 1,967; 1,043 of ITOT's positions don't appear in IWM at all, and they are 95.6% of ITOT by weight.
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Related comparisons
Sources: issuer holdings files, ITOT as of 2026-07-23, IWM as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.