Southeastern Asset Management has filed a 13D showing a 15.2% stake in DineEquity Inc (NYSE:DIN). The value based firm managed by Mason Hawkins owns 2,798,762 shares outstanding. Mason Hawkins has decreased his stake in the owner of the famous food chains, IHOP and Applebee’s. According to Southeastern Asset Management’s Q3 13F, the value firm owned 16.87% of DineEquity Inc (NYSE:DIN), or 3,109,600. Interestingly, another value firm filed recently purchased a 5.73% stake in the Glendale, California based company. Marcato Capital Management, a hedge fund started by Richard “Mick” McGuire, filed a 13D showing the large holding yesterday. Prior to the starting…