Mutual Fund Manager
  
See: Mutual Fund.
The manager is the person or group of people who call the shots, buying and selling big blocks of stocks and bonds, hoping to beat their index, or whatever "bogey" or hurdle they're given as their relevant index target. Beat the market, and they get paid handsomely; lose to index funds and they get fired and/or their fund shrinks into oblivion.
The managed money mutual fund industry is dying, as index funds have done vastly better over time than mutual funds in today's hotly competitive and contested markets, where picking winners has become way harder than it was in the 1960s when mutual funds were a growth industry.
If the gig still tickles you, though, you can read all about it on Shmoop.