An auction settlement is the extra, follow-up settlement cycle the exchange runs when a seller fails to deliver shares in the normal cycle. The clearing corporation buys the missing shares in a special auction session and delivers them to the buyer. A day or two later than normal, but the buyer is made whole and the defaulting seller bears the cost.
Where does it fit in the settlement timeline?
Think of it as a repair loop bolted onto the regular settlement cycle. In the normal course, an equity Delivery trade settles on T+1: sellers deliver shares at pay-in, buyers receive them at pay-out, done.
But pay-in is a hard deadline, and sometimes a seller's shares simply aren't there, a short delivery. The regular cycle can't wait for one defaulter, so it completes for everyone else, and the shortage is split off into its own mini-cycle:
| Day | Regular cycle | Auction cycle (only if delivery fails) |
|---|---|---|
| T | Trade executed | — |
| T+1 | Pay-in and pay-out; shortage identified | Auction session held to buy the missing shares |
| T+2 | — | Auction settlement: shares delivered to the buyer |
So if you're the buyer in a short delivery, your shares typically arrive on T+2 instead of T+1 (one settlement cycle late) or, if the auction can't source them at all, you receive cash compensation through a close-out instead.
What actually happens in the auction?
The clearing corporation invites other market participants who hold the stock to sell it in a separate auction session, buys the required quantity there on the defaulter's behalf, and routes the shares to the original buyer. The full mechanics, who can offer, the price band, and the close-out formula when no shares are found. Are covered in how does the auction process work when there's a short delivery? This article's point is simpler: the auction is a second settlement, with its own pay-in and pay-out, stitched onto the first.
Who pays for it?
The seller who failed to deliver. Rahul short sells 100 shares of Godavari Foods intraday and can't buy them back before close. The stock is locked at its upper circuit. His failed delivery goes to auction, and whatever the shares cost there (often more than he sold them for), plus penalties, is debited to him. The rupee-level consequences are worked through in short delivery: settlement and cost.
The buyer pays nothing extra, the auction exists to protect them.
Things to keep in mind
- An auction settlement is rare and exception-driven, the overwhelming majority of trades settle in the normal cycle without one.
- As a buyer, a short delivery only costs you time: shares land about a settlement cycle late, or you're compensated in cash via close-out.
- As a seller, never let a delivery obligation fail. Auction prices plus penalties routinely exceed the original trade value.
- Selling shares that haven't reached your demat account yet is the everyday way retail investors stumble into this. See what happens if I sell shares before they are delivered to my demat account?
Read next
How are F&O trades settled? — Derivatives settle on a different cycle, and in a different way.