VB vs CSPX overlap

3.2% by weight, as of September 30, 2026: little overlap. 132 companies appear in both funds; they make up 23% of VB and 3.2% of CSPX.

The largest shared positions are MRNA, P, TWLO, ILMN and FLEX. Ranked by the smaller of the two weights, which is the part you would own twice.

Out of every $100 split evenly between them, about $3 (half in each fund) buys identical positions. The rest is exposure only one of the two funds gives you: 1,169 names only in VB, 372 only in CSPX. Half in each behaves like 163 equally weighted stocks, against 674 for VB alone and 44 for CSPX alone. Whether that duplication is a problem depends on the mix you want; this is a description, not advice.

CSPX is iShares Core S&P 500 UCITS ETF (ISIN IE00B5BMR087), an Irish-domiciled UCITS fund on the S&P 500 index. Next to VB, 3.2% of the money is the same, spread over 132 companies both hold, as of September 30, 2026.

Yes. CSPX also trades as CSP1 (London, GBP), SXR8 (Xetra, EUR) and CSSPX (Borsa Italiana, EUR). Each is the same portfolio in another currency, on another exchange or paying its dividends out, so VB vs SXR8 also overlaps 3.2%.

For every company held by both funds we take the smaller of its two weights and add them up. The weights come from the full holdings files Vanguard and iShares publish, not a top-10 sample, and companies are matched by their ISIN so share classes stay apart. Sector overlap applies the same rule to the issuers' sector labels; "behaves like N equally weighted stocks" is one over the sum of the squared weights.