BTST (Buy Today Sell Tomorrow) trades involve purchasing and selling shares at your discretion on the next trading day (T+1) or even before the trade is settled, meaning the shares have not yet been delivered to your DEMAT account. The risk associated with BTST trades lies in relying entirely on the seller from whom you purchased the shares. If the seller defaults on delivering the purchased shares, known as short delivery, you may face auction penalties of up to 20% of the value of the short-sold shares. To protect customers' interests, margins received against BTST trades cannot be used to create new positions.