12. Diane Morais, Ally Bank

President and CEO, Ally Bank

Diane Morais has been driving a transformation at Ally Bank since she took over as president and chief executive in March 2015.

Best known for online deposit gathering and auto lending, Ally has been branching out to meet customer demand and to improve the bottom line. In April of this year, the company announced a deal to buy the online brokerage TradeKing. Then in June, Ally introduced its first credit card. It also plans to re-enter the mortgage business this year. Morais (who reports to holding company CEO Jeffrey Brown) is leading the charge on all three fronts.

The changes haven't always been smooth. Investors have been unhappy with Ally's performance. An activist shareholder, Lion Point Capital, challenged Ally to look for a potential buyer until the company agreed to appoint an independent director. Morais and her team have worked to communicate their vision by speaking at conferences and holding the company's first-ever investor day in February.

Although the negative scrutiny can be frustrating, Morais said she concentrates on getting results and proving that the company's strategy is working.

"You have to focus on delivering and executing on what we said we would do," Morais said. "The expectation or hope is that when we deliver the results, the stock price will follow."

Morais said she has benefited from many mentors throughout her career and tries to pay it forward by working with a "long list" of those she advises at Ally and her previous employer, Bank of America. She counsels women looking to advance their careers to cultivate a network and keep it active. "Someone who really gives you that perspective and challenges you is invaluable," Morais said.

"If there is something you are interested in, if you are missing something, figure out how to get it. Use that mentoring network to help you."