Every stock trade has a buyer and a seller, and the seller is expected to deliver the shares by the settlement deadline. When a seller can't — a short delivery — the buyer must still get what they paid for. The stock exchange handles this through its clearing corporation, which runs an auction to buy the missing shares and deliver them to the buyer. The seller who fell short pays whatever that costs, which can be well above the price they sold at.
What is a short delivery?
A short delivery happens when a seller doesn't hand over the shares they sold by the settlement pay-in. Common reasons:
- An Intraday short sell that couldn't be bought back before the market closed — usually because the stock was locked at its upper circuit with no sellers.
- Selling shares that weren't actually available in the demat account on the settlement day.
Because the shares never arrived, the exchange can't simply pass them to the buyer — so it steps in.
What happens in the auction?
Under the current T+1 settlement cycle, the shortage is identified on the settlement day, and the exchange's clearing corporation conducts a buy-in auction the same day:
- The clearing corporation invites eligible sellers to offer the short-delivered shares in a separate auction session.
- Offers are placed within a set price band around a reference price.
- Matched shares are bought on the defaulting seller's behalf and delivered to the original buyer, with the auction settlement completed the next day.
The buyer is kept whole throughout — they receive the shares (or cash compensation) regardless of the seller's failure.
What if no shares are available in the auction?
Sometimes the auction can't source the shares — for example, the stock is still locked at its upper circuit and no one is offering to sell. The trade is then closed out in cash instead of shares. The close-out price the seller is charged is the higher of:
- the highest price the stock traded at from the trade day up to the auction day, or
- 20% above the stock's closing price on the auction day.
That amount is recovered from the seller and used to compensate the buyer.
What does a short delivery cost the seller?
The defaulting seller is debited the higher of the auction price or the close-out/valuation price, plus any penalties and charges the exchange levies. Because the close-out formula is deliberately punitive — and because a rising stock (like one at its upper circuit) keeps climbing — a short delivery can cost significantly more than the trade itself. This is why an open short position that can't be squared off is best avoided.
Is the buyer affected?
No — the mechanism exists to protect the buyer. Whether the shares come through the auction or the trade is closed out in cash, the buyer receives what they're owed. The cost and penalty fall on the seller who failed to deliver. If you were the buyer and got cash instead of the shares, see why your fund balance went up but the shares are missing from your holdings.