Short selling

Selling a borrowed share in the expectation of buying it back later at a lower price, returning it to the lender and keeping the difference.

A short seller borrows shares (from a broker, who borrows them from a long holder such as a pension fund), sells them in the market, and later buys the same number of shares back to return them. If the price fell in between, the difference is the seller's profit; if it rose, the loss, which has no upper limit because a share price can keep rising.

The regulatory data on this site measures disclosed net short positions, not individual trades: how much of a company's capital is held short on a given date, as reported to or published by a regulator. It cannot show who sold when, at what price, or why.