IWM vs. VB vs. SCHA: Small-Cap ETF Baskets and Index Rules

“Small cap” is not one universal company list. The index provider sets the eligible universe, size boundary, constituent count or market-cap range, review calendar, and weighting method. Those choices shape which companies enter, how long existing members remain, and which names become large positions. A ticker comparison therefore needs the benchmark rules as well as the fund’s latest holdings.

The holdings counts are portfolio counts reported by the ETF sponsors. They are not a synchronized count of index constituents: a fund can hold cash, derivatives, or implementation positions, and its holdings file can differ from the index provider’s count. Vanguard reported 1,301 benchmark stocks alongside 1,306 fund stocks for VB on July 31. LSEG reported 1,996 Russell 2000 securities at its April 30 rank date; that is a separate index-date statistic, not IWM’s September fund count. See the iShares IWM profile, Vanguard VB profile, and Schwab SCHA profile.

The Russell 2000 is a size segment within FTSE Russell’s U.S. equity index family. Eligible U.S. companies are ranked by total market capitalization at the rank date; the Russell 2000 represents roughly the next 2,000 smaller companies after the Russell 1000 segment. Current-member buffers, investability rules, and quarterly IPO additions mean it should not be treated as a permanently fixed list of companies ranked exactly 1,001 through 3,000. FTSE Russell’s August 2026 ground rules schedule full reconstitution in June and December, with the 2026 calendar setting the June and December implementation dates. The current Russell construction rules and reconstitution page describe those procedures.

VB’s current benchmark is the Morningstar US Small Cap Index. Morningstar’s live index profile identifies it as a float-adjusted market-cap-weighted U.S. equity index with quarterly reconstitution and quarterly rebalancing. This is a market-size segment with a changing company count, not a fixed 2,000-stock basket. Vanguard uses a full-replication approach and its July 31 profile showed 1,301 benchmark stocks. The current Morningstar index profile shows its weighting and review schedule.

SCHA follows the Dow Jones U.S. Small-Cap Total Stock Market Index. Under the current S&P DJI methodology, annual size assignment ranks eligible constituents in the Dow Jones U.S. Total Stock Market Index by total company capitalization, applies buffers for existing members, and targets 1,750 small-cap companies. Companies not selected for the large-cap index that rank at or below the small-cap boundary can enter; existing small-cap members ranked 3,000 or higher are retained first until the target is reached. The index weights constituents by float-adjusted market capitalization. Quarterly updates can add eligible IPOs and other newly investable securities, while current members are not fully re-evaluated for continued inclusion every quarter. The rules are in S&P DJI’s Dow Jones U.S. Total Stock Market Indices methodology.

These differences matter at the edges. Russell’s count-based segment, Morningstar’s market-cap segment, and Dow Jones’s 1,750-member target can include overlapping companies while disagreeing about borderline companies and review timing. Similar broad exposure does not make the complete portfolios identical.

Before July 29, 2026, VB’s target index was named the CRSP US Small Cap Index. On that date, Vanguard changed the fund’s name to Vanguard Morningstar Small-Cap ETF and the index’s name to Morningstar US Small Cap Index. Vanguard’s SEC supplement states that the name changes were effective July 29 and that the funds’ investment objectives, strategies, and policies remained unchanged. Morningstar had acquired CRSP and announced that its CRSP Market Indexes would be rebranded under the Morningstar name while preserving their methodology.

For continuity, an older analysis that calls VB’s benchmark “CRSP US Small Cap Index” is referring to the prior name in the same index lineage; the July 29 rename alone does not mean VB changed its intended small-cap exposure. Check the analysis date and the holdings date before reusing any old weights. The latest available Vanguard portfolio here is July 31, two days after the transition, and its profile uses the Morningstar name. See Vanguard’s July 29 SEC supplement and Morningstar’s rebrand announcement.

BlackRock’s September 24 holdings CSV reports 1,983 equity positions for IWM. Its ten largest stock weights add to approximately 3.33% using the CSV’s published weights rounded to two decimal places. The list below follows the issuer file order; several positions are tied at 0.30% after rounding, so the exact ordering around the cutoff should not be over-read.

The broad dispersion across the largest holdings is consistent with a basket of nearly two thousand stocks: even the first-listed position is 0.40% in this snapshot. That observation describes IWM’s reported portfolio on one date. It is not a prediction of future concentration or performance. The IWM holdings CSV labels its portfolio date as September 24, 2026.

Vanguard’s latest profile lists 1,306 VB holdings and 1,301 benchmark stocks as of July 31, 2026. Its ten largest reported stock positions total 4.08% based on the displayed two-decimal weights.

This is a post-name-change portfolio snapshot. Its date precedes the September IWM and SCHA reports by nearly two months. Therefore, do not read the 4.08% beside their September totals as a same-date claim that VB is more concentrated. It is a useful view of VB’s dated leading positions and small-cap basket, not a synchronized portfolio comparison.

Schwab reported 1,757 SCHA holdings on September 24. Its displayed top ten positions total about 3.03%, but one is GVMXX, a government money-market holding rather than an operating-company stock. Excluding that 0.38% cash investment, the nine displayed equities add to approximately 2.65%.

This distinction matters when comparing concentration: the cash fund belongs to the ETF portfolio but not to the small-cap stock index. Schwab’s page separately reports 99.60% stocks and 0.40% cash investments on September 24. The SCHA profile’s sector table is older, however; its sector weights below are dated June 30 rather than September 24.

The largest sector labels differ in the issuers’ latest available sector tables. IWM’s page dates its sector breakdown September 24; Vanguard’s VB breakdown is July 31; Schwab’s SCHA sector table is June 30. Vanguard uses ICB categories, while Schwab explicitly identifies GICS for its portfolio sector classifications. The categories and dates are not perfectly aligned, so the table is descriptive rather than a strict sector-weight ranking.

These figures show that small-cap benchmarks need not have the same sector mix. They do not establish that one fund is currently more technology-heavy than another because the reporting dates differ and the sponsor taxonomies are not identical. See the iShares sector breakdown, Vanguard portfolio profile, and Schwab SCHA portfolio page.

IWM and SCHA both have September 24 issuer snapshots. Their displayed top-ten lists share two tickers: TWST and HUT. On that date, those two names represented 0.75% of IWM’s assets (0.40% + 0.35%) and 0.56% of SCHA’s assets (0.29% + 0.27%), using displayed rounded weights. This is a same-day comparison of two names visible in each top-ten sleeve, not the complete overlap ratio of the funds.

VB’s newest portfolio date is July 31, so its constituent and weight data are not synchronized with the September 24 IWM and SCHA files. A full overlap calculation needs complete same-date holdings plus consistent identifier matching—ISIN first, then CUSIP or LEI where appropriate—and a consistent treatment of cash and non-equity positions. Ticker-only matches can miss share-class, identifier, or corporate-action details. The useful conclusion is that the strategies occupy related U.S. small-cap territory, while the displayed top-ten evidence does not support a three-fund exact overlap percentage.

The current sponsor pages list expense ratios of 0.19% for IWM, 0.03% for VB, and 0.03% for SCHA. On a hypothetical balance held constant at US$10,000 for one year, that is about US$19 for IWM and US$3 for either VB or SCHA—a simple arithmetic difference of US$16 per year between IWM and the 0.03% funds. Schwab says its 0.03% ratio became effective June 11, 2026; Vanguard’s profile dates VB’s ratio to April 28, 2026; iShares reports its expense ratio as stated in the current prospectus.

This illustration is not a bill or forecast. Fund assets and expenses vary with balances and time. Expense ratios also do not capture every cost: bid-ask spreads, brokerage charges, taxes, tracking differences, and portfolio trading can affect an investor’s actual result. Compare current prospectus disclosures and executable trading conditions rather than treating the lowest ratio as the whole cost picture.

Start with the exposure question. IWM is tied to Russell’s roughly 2,000-company small-cap segment; VB follows a cap-weighted small-cap segment whose benchmark was renamed in July; SCHA follows a Dow Jones size segment targeting 1,750 companies. Then align the holdings date, include the same asset types, and compare sector mappings before calculating differences. For an exact basket overlap, use all holdings on the same date and permanent identifiers—not just the ticker labels in a top-ten panel.

Here, IWM and SCHA have matching September 24 dates for their top-ten observations, but only two shared top-ten names can be verified from the displayed sleeve. VB’s July 31 report is post-transition but not aligned to those September reports. No synchronized three-fund holdings set is presented, so no full overlap percentage or current three-way concentration ranking is claimed. The article compares index design and dated portfolio evidence; it does not rank returns or recommend a fund.