Why are sale proceeds not immediately available for withdrawal?

This comes down to the settlement cycle: even though your sell order executed and the trade shows as complete, the actual movement of funds through the clearing corporation takes until T+1 (one business day after the trade) to finalise under India’s current settlement system. The exchange and clearing house need this window to verify and finalise the transaction on both sides, buyer and seller, before funds are officially settled and safe to release for withdrawal. Brokers often let you use unsettled sale proceeds for further trading margin sooner than that, since that’s an internal risk decision the broker makes, but withdrawal to your bank account follows the stricter settlement timeline since it involves money actually leaving the broker’s regulated pool account. You think of trade execution and cash settlement as two different milestones, only the second one, which takes an extra business day, makes funds withdrawable.