FORTUNE's annual ranking of America's leading businesswomen

30 of 50
30. Pam Nicholson
Pam Nicholson
President and COO
Enterprise Holdings
2011 rank: 26
Age: 52
Under Nicholson's leadership, privately held Enterprise is expanding: A European acquisition last year added 30,000 vehicles to the transportation company's fleet, which totals more than 1 million cars. And Enterprise recently bought two East Coast car-sharing firms to help it take on Zipcar.
From the October 8, 2012 issue
How we pick the Power 50
The list is compiled by FORTUNE editors, who consider four criteria: the size and importance of the woman's business in the global economy, the health and direction of the business, the arc of the woman's career (resume and runway ahead), and societal and cultural influence.