Steven Rattner

SPHERE OF INFLUENCE: Rattner’s investment firm has big stakes in media companies such as Cablevision, MGM, and Alpha Media Group (Maxim, Blender). He also enjoys playing the role of public intellectual, churning out opinion pieces on weighty subjects such as the federal budget deficit, hedge-fund regulation, the housing crunch, and the fate of newspapers, which he thinks should ultimately be converted to nonprofit public trusts or some new hybrid.

NEIGHBOR RELATIONS: Reportedly persuaded Comcast’s Brian Roberts, a longtime client, to buy out a Martha’s Vineyard neighbor that Rattner, 56, had feuded with.

BIG DEAL: New York mayor Michael Bloomberg announced in January that he was putting his wealth (estimated at more than $11.5 billion) under Quadrangle’s management to avoid any conflicts of interest.