2. Marianne Lake, JPMorgan Chase

Chief Financial Officer, JPMorgan Chase

Marianne Lake has come up with a simple formula to mentor rising stars.

During American Banker's Most Powerful Women in Banking gala last year, Lake laid out the "30-5-1" challenge. She asked those in the audience to each week spend 30 minutes having coffee with a talented junior woman, five minutes congratulating a woman on a recent success and one minute talking up that woman to another senior peer.

The initiative has now become a firmwide phenomenon at JPMorgan Chase, injecting new energy into the movement to support women across the company. During Women's History Month in March, Women on the Move, an internal initiative launched in 2013 to encourage senior women globally to advocate for female co-workers, hosted a "30-5-1" day at JPMorgan's headquarters.

Lake also co-sponsored a pilot program that aims to support parents who are about to go on or return from leave. The effort is expanding to include a dedicated program manager and an online portal that helps to match expectant parents with mentors who have already taken parental leave.

Lake has been chief financial officer since 2013 and her influence at the nation's largest bank has grown steadily since, particularly with the investment community. She is now an active participant on quarterly earnings calls and investor road shows, and last year she led a number of group and one-on-one meetings with major shareholders.

Under Lake, the finance department is investing heavily in robotics technology that, once perfected, would allow robots to perform certain labor-intensive activities so that employees could focus on "higher-value activities."

JPMorgan Chase spends about $9 billion a year on technology.