Martha H.W. Crowninshield

61 Martha H.W. Crowninshield57 , managing director , Boston Ventures ManagementClout : 13 Influence : 38 Power : 51Boston Ventures closed one of the biggest , and quietest , deals in the state last year when it sold Six Flags Entertainment for $1.9 billion.That's in character for Crowninshield , who prefers a low profile-except on the charity circuit.Her yearly $100 , 000 check is the largest annual gift from an individual to the United Way , and she likes to bankroll women running for office.She's also now a part-owner of Ms. magazine.