Although women are better educated than ever before and often start their careers as equally qualified as men, they still lag men when it comes to career progression and making it into the leadership ranks of corporates. Women in the U.S. occupy around half of management, professional and related occupations, according to Catalyst, but only 14% of executive officer positions. It’s a similar story across the globe.

Mentoring was long the reputed answer to this ‘gender gap’. Sociologists Frank Dobbin, Alexandra Kalev and Erin Kelley have researched corporate diversity management programs across America and found that women at companies with formal mentoring programs and diversity councils do succeed, in general, in advancing to more senior positions.

Other experts have gone a step further. Sylvia Ann Hewlett, an economist and author of the book Forget a Mentor, Find a Sponsor, argues that mentoring is not enough; it needs be augmented by sponsorship. A mentor gives advice and feedback, but expects little in return. By contrast, a sponsor has skin in the game. Because sponsors believe in their protégés’ long-term potential, they openly advocate for them and give them the room to take risks and shine. Hewlett sums it up: “Mentors give, whereas sponsors invest.”

Like every investment, the risks and return are correlated. “Someone is not going to take a bet on you and openly advocate for you unless they believe you are exceptionally capable. Because there is risk: you are walking around with the brand of the sponsor on your forehead and the protégé is a projection of the sponsor’s power. There has to be tremendous trust and reliance that the protégé can deliver,” says Hewlett.

Lara Warner from Credit Suisse is an example of how sponsorship works in practice. She joined Credit Suisse in 2002 as a telecom research analyst. Her potential was recognized early on, and by dint of her performance and loyalty, she ‘came through’ for her former sponsors. Warner continued to rise further in the bank, and today she is COO of Credit Suisse’s Investment Banking Division.

Although Warner is now in a senior management position, she needs support from the most powerful people at Credit Suisse to help her climb higher. This year she joined nine other very senior women at Credit Suisse like herself for a mentoring and sponsorship program called the Executive Mentoring Advisory Group (EMAG). EMAG matches each woman with one member of Credit Suisse’s Executive Board, the team of eight senior executives who lead the bank.

“I have benefited a great deal from sponsorship in my career, and EMAG is important to me personally as I continue to progress my career,” says Warner. Her sponsor, Robert Shafir, Head of Private Banking & Wealth Management and CEO Americas at Credit Suisse, gives Warner unfiltered feedback on various issues, fulfilling the traditional role of a mentor. But they also exchange views about Credit Suisse’s strategy and Warner’s career aspirations, and he champions Warner across the bank.

“Everyone on the board is investing a lot of time in their sponsor role, but we can’t do it alone,” says Shafir. “If our protégés in turn make their own management teams more diverse, we will eventually reach a tipping point in gender balance. Sponsorship has to happen at every level to be truly impactful.”

Warner is doing just that. She not only receives sponsorship from Robert Shafir, but is also a sponsor to others. She says: “I’m not only supporting my protégés in their day- to-day roles, but also thinking about the key development and mobility opportunities they need to be successful in the future.”

The idea to create a sponsorship program for Credit Suisse’s most senior female executives came from CEO Brady Dougan. He says, “Our objective as sponsors is to ensure that the most senior executives of the bank meet these exceptional women and have a chance to see how talented they are. It takes active sponsorship by senior leaders to help diverse talent make it all the way to the top. Sponsorship should be the breakthrough to create a more critical mass of women at the senior level, and hopefully on our Executive Board.”

Marisa Drew, another EMAG participant, believes the bank’s investments in sponsorship will pay off through new business – in particular from other women. “The number of women who are ascending to positions of power and influence, for example on boards, is increasing. More of the world’s wealth is now controlled by women, whether it’s young budding entrepreneurs in Asia or women who inherit wealth and are looking for advice on how to deploy that wealth. There is a comfort level for women to be banked by other women. Our client base will demand that the organizations that serve them have diversity; they don’t want to be served by mono-gender organizations.”

Senior women like Drew and Warner are not the only beneficiaries of sponsorship at Credit Suisse. Formal sponsorship programs are also available to staff at all levels. The bank’s first sponsorship program for female managing directors started in 2011 with 33 women. Within two years, half of them were either promoted or assumed additional responsibilities.