"ATST" is Acquire Today Sell Tomorrow. This facility allows clients to sell stocks (acquired on T day) on T + 1 day even before the actual delivery comes into client demat account.

If the stock bought yesterday can give you profit today, we provide you with an option to sell the stock purchased yesterday, even before the delivery of stock has come to your demat account.

To put an order as "ATST", client has to select product type as "CNC".

There is a settlement auction risk involved in such type of transactions.