Yahoo's sharesOutstanding returns only the listed class on dual-class foreign issuers

Claim

Yahoo Finance (and fin.py, which surfaces the same field) reports sharesOutstanding as the listed class only on dual-class issuers. Unlisted Class B / founder / super-voting shares are omitted. Meanwhile marketCap in the same response is computed off impliedSharesOutstanding, which is correct.

The two fields therefore contradict each other, and the contradiction is the detection method.

Detection — a five-second check that should be routine

marketCap ÷ price vs sharesOutstanding

If they disagree by more than rounding, the share count is wrong. Cross-check against diluted weighted-average shares on the income statement, then confirm the true total from the 20-F/10-K cover page or the equity note.

Evidence

NU (Nu Holdings), 2026-07-31. Yahoo reported SharesOut 3.81B at a price of $14.33 — implying a $54.6B market cap against a reported MktCap of $69.22B. The true figure from the Q1'26 6-K was 4,861.7M (Class A 3,839.1M + Class B 1,022.6M). Diluted weighted-average was 4,910.3M.

The error is 27%. Any per-share metric computed from the raw field — book value per share, FCF per share, revenue per share, EPS cross-checks — is overstated by that margin, and a valuation built on it would have been badly wrong in the bullish direction.

Why foreign private issuers are the high-risk case

An FPI files a 20-F, not a 10-K, and its share-count disclosures do not always populate the vendor's expected fields. The dual-class structure is common in recent LatAm, Israeli and Asian listings, and in founder-controlled US tech. The combination — dual class and FPI — is where this reliably breaks.

Rule

On any dual-class or foreign issuer, establish the fully diluted share count from the primary filing before computing a single per-share number, and state which figure you used. Do not take it from a vendor field, and do not assume marketCap and sharesOutstanding came from the same source.

What would falsify this

Yahoo populating sharesOutstanding with the consolidated total across share classes. Re-test the reconciliation on any dual-class name before trusting the field again — this is a vendor behaviour, not a permanent law.

[[principle-primary-source-beats-vendor]] · [[pitfall-vendor-revenue-is-net-construct-for-banks]] · [[pitfall-yahoo-mixes-cad-usd-on-cross-listed-issuers]] — the same family of vendor failures concentrated on non-US listings.

History

2026-07-31 — found in the NU analysis. Caught only because market cap and share count failed to reconcile; nothing else in the payload signalled a problem.