An bill is a settlement document issued when a customer fails to deliver stocks they sold. In such cases, the exchange conducts an auction to buy the undelivered from the auction market and deliver them to the buyer. The bill reflects the obligation against the auctioned quantity, along with any penalties levied.

For example, if a trader sells 100 shares at ₹500 each but fails to deliver them, the exchange will buy these shares in an auction. If the close-out price is ₹600 per , the trader must pay the ₹100 difference per share, plus any imposed penalties.

The auction bill is typically issued on the next trading day after the auction is completed.