Why are sold holdings bought back on the same day?
Sold holdings are bought back on the same day before the market closes when MIS is selected instead of CNC. The MIS product type is used for intraday trading, and if chosen for selling holdings, it creates a new sell intraday position. This position needs to be squared off by buying the stock on the same day before the market closes, or the position will be auto-squared off by Zerodha and a charge of ₹50 + 18% GST will be levied. To learn more about MIS and CNC product types, see What does CNC, MIS and NRML mean?