Supercharging your career requires setting up “an inside job.” And I’m not talking about robbing a bank!

You need a sponsor—someone “on the inside.” It’s a person with clout who can advocate for you from behind closed doors, fight for you to get great opportunities, and spread the word about your achievements. “That’s perfect for her, she’s ready,” a sponsor might say, or “let’s give her a shot.”

Just because you have a mentor doesn’t mean you are being sponsored.  Mentors show you the ropes and teach you about the unwritten rules in your organization, but they don’t always pull you up the ladder.

The latest report from Catalyst, the world’s leading non-profit expanding opportunities for women and business, highlights the impact sponsors can have on your career. We asked more than 4,000 MBA alumni from top schools in Asia, Canada, Europe, and the United States about their salaries, promotions, and relationship with their mentors. We discovered that women and men were equally likely to have mentors, but men’s were more senior.

And that can make all the difference.

Men’s mentors had more clout and were therefore in a better position to provide sponsorship. This helps explain why men in our survey received more promotions and greater salary increases than women. For example, when we compared men with mentors to women with mentors, the men’s starting salaries were more than $9,000 higher. Men climbed the ladder more quickly than women too, and each promotion came with far greater pay increases—an extra 21% in compensation for men, but only an extra 2% for women!

These findings go a long way in explaining why—for five years straight—women’s advancement into business leadership has stalled in most of America’s top companies. Our 2010 Census of women leaders in the Fortune 500 revealed that 27.4% of companies had no women executive officers—the list may surprise you—and 12.1% had no women board members. Across all F500s, men held 85.6% of executive officer positions and 84.3% of corporate board seats, and chaired a staggering 97.4% of all boards. And women made up just 7.6% of the top earners.

Companies that overlook women miss an opportunity to pick from the best talent and get better returns for it. Catalyst research shows that companies with the highest representation of women on their top management teams, on average, experienced better financial performance than companies with the lowest: 35% higher Return on Equity and 34% higher Total Return to Shareholders. We found even greater financial performance when more women serve on corporate boards, and performance spiked further when three or more women served together.

Gender diversity at the top leads to greater independence, innovation, and creative thinking throughout an organization—all critical to good governance and increasing shareholder value. Businesses that overlook women lose out on half the available talent. That’s like trying to run a marathon with only one sneaker. You might hobble along, but you definitely won’t win the race!

This is why sponsorship is so important—it’s one key to advancing more women into business leadership.
Women should look for companies that value sponsorship. Many businesses promote mentorship, but that isn’t always enough. Women often receive ongoing career development without an impact on pay or job level. Some said they were “mentored to death.”

If your organization does not have a formal sponsorship program, do not simply wait for one to come along. Sponsorship is not an entitlement—you have to “earn it” by being a top performer. By doing a great job, promoting your work, and finding opportunities to connect with senior management, you’ll attract a sponsor. Their gender doesn’t matter. What does is the influence they wield in your organization.
So seek a powerful sponsor—a person “on the inside” who can get your career off the runway and take it to new heights.

Ilene H. Lang is president and CEO of Catalyst, the leading nonprofit working globally to advance women and business. She is the mother of three adult children. Follow Ms. Lang’s blog Catalyzing and Catalyst’s tweets @catalystinc.