Yes you can buy securities against the sales proceeds generated from the sale of the shares under Inter Settlement (IS). Your buying limits increases immediately based on the sale proceeds that you are expected to receive from AxisDirect on the settlement day.For e.g., You bought 100 shares of Axis Bank at Rs. 1500 on 18 May 2009 and therefore the total trade value is Rs. 1,50,000. On 19 May 2009 you sell 100 shares of Axis Bank at Rs 1650 with the total trade value of Rs 1,65,000. Therefore a sales proceeds of Rs 1,65,000 will be generated. This will increase the trading limit and you can utilize this limit to buy more securities

This process applies for only eligible scrips for intersettlement.