Irene Dorner might not be running the U.S. banking operations of HSBC Holdings today if it hadn't been for "an intervention" from a top corporate executive she met through a mentorship program a few years back.

Though Dorner was one of HSBC's highest-ranking women in the U.K. at the time, her mentor, the chairman of a large industrial firm, told Dorner that her career could stall if she didn't communicate to her bosses what she wanted to do next.

So, on that advice, Dorner prepared a one-page note explaining that, after 15 years running various business lines, she was ready to head an entire banking region. Three months later, Dorner was named chief executive of HSBC's bank in Malaysia.

"It was great advice," says Dorner. "I was offered that posting because I cleared the communication lines."

Dorner says that three-year stint in Malaysia-she calls it her "first solo flight"-also paved the way for her promotion to CEO of the vastly larger HSBC USA earlier this year. The U.S. banking environment is so complex, she says, that "it would not have been possible to do this job without having been CEO in another country."

Dorner, 55, is clearly invigorated by the challenge of running the U.S. operation, which has $184 billion of assets and nearly 500 branches.

In the U.S., HSBC has been moving away from consumer lending and returning to its roots as one of world's largest financiers of global trade. Dorner's mandate is to help corporate and private-banking clients do business in all 88countries where HSBC operates, and she's come away from visits with employees andcustomers convinced that American firms are eager to do more business overseas. "This is the biggest entrepreneurial country in the world and will be for some considerable time," she says.

Niall Booker, the CEO of HSBC North America, says Dorner is a "skillful executive with a proven track record of building strong relationships with customers, employees and regulators." He also says she has a well-deserved reputation for integrity, often explaining her positions on matters by saying "it's the right thing to do," then supporting an ethical stance with a compelling business case.

A lawyer by training, Dorner was in-house counsel at HSBC in the early 1990s when she was offered a job heading up strategic planning after a merger with Midland Bank.

It was a difficult decision-especially after she told her mother who had "paid good hard cash" to send her to law school. But she took the leap because she felt it would enhance her development.

After 10 years running various support functions, including marketing and human resources, she was encouraged by an executive coach to move into positions running income-producing businesses. She started taking on such roles as general manager of wealth management and general manager of the HSBC's Northern England, Scotland and Northern Ireland division.

With that range of experience, Dorner knew by 2007 that she was ready to become a CEO-she just needed someone to tell her to go for it.

Her advice now to anyone looking to move up the corporate ladder?

"If you want something, you have to ask for it," she says. "Your employer is not telepathic."

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