After a four-year hiatus, ace investor Rakesh Jhunjhunwala has raised his stake in Aptech, the only investment where he holds management control. Since August this year, Jhunjhunwala has mopped up 14.63 lakh shares through bulk deals on the NSE at an average price of Rs.129 per share, to take his overall holding to 49.30% from 45.28%. The last tranche on September 7 saw the investor pick up 7.63 lakh shares at an average price of Rs.149.11 a share, cumulatively worth Rs.11.54 crore. Post the acquisition, the stock has surged 36% to Rs.175.