Can short interest exceed 100%?

Yes, and it does not require anything improper. The same share can be borrowed, sold short, bought by a new investor, lent out again and shorted again. Each short sale in that chain is a real position against the company, so the sum of short positions can exceed the number of shares in issue, even though no more shares exist than were issued.

The mechanics

1. Fund A borrows a share and sells it short. The buyer, B, now owns it.
2. B's broker lends the same share to fund C, which sells it short too.
3. One issued share now backs two open short positions, 200% of that share.

Scale that up and a heavily shorted company can report aggregate short interest above its entire issued capital. The best-known case is GameStop in January 2021, where reported short interest exceeded the available float. Nothing in the arithmetic breaks: every lender is owed a share, every borrower owes one, and unwinding requires the same shares to be bought back through the chain.

What our data shows, and where 100% can be breached

• US: FINRA short interest divided by shares outstanding can and does exceed 100% (GameStop printed above it in January 2021), because the same share can be lent, shorted and re-lent. Our US figures are that regulatory count against each company's SEC-filed share total.
• Australia: ASIC's aggregate counts nearly all reported positions, and its file occasionally reports positions above 100% of units on issue, we have observed 160% on a thinly issued quoted-debt stub. On ordinary shares the aggregate can legitimately approach or top full issuance in extreme episodes.
• UK: the FCA's ANSP sums only positions of 0.2% or more per manager, each net of that manager's long exposure. Exceeding 100% would need many large managers net short simultaneously, arithmetically possible, never yet observed in the publication.
• Europe (France, Netherlands, Norway, Sweden): the named registers publish only positions of 0.5%+ per holder, so the published sum is a floor. The registers' highest company aggregates on record in our dataset sit far below 100%; see the French and Dutch all-time records.

Net vs gross: why definitions matter

Regulatory disclosures are net positions: a manager long 1% and short 3% reports 2%. US-style "short interest" (shares borrowed and sold, reported by brokers) is closer to a gross measure. Gross measures exceed 100% more easily; net-per-manager regimes make it harder. Comparing figures across regimes without checking the definition is the most common way to get this wrong.

This page is educational. Nothing on this site is investment advice.