CEO, Citibank | Citigroup

When Citigroup encounters its next big, nettlesome problem, it's a good bet that Barbara Desoer will be called on to fix it.

In 2012 and 2013, the New York-based megabank was hit by a pair of regulatory orders connected to deficiencies in its anti-money-laundering program. Upon joining Citi in 2013, Desoer took responsibility for overseeing the bank's AML efforts.

At the time, Citi had two separate global units dedicated to the prevention of money laundering. One of the groups focused on regulatory compliance, while the other handled the operational aspects of monitoring roughly 750 million transactions around the world each month.

Last year, the bank combined those two units to create a global AML organization — a move that the bank says was unrelated to its regulatory problems. The combined unit has two co-heads: Allison Clew, a former AML consultant at Deloitte, and Denise Reilly, a Citi veteran, both of whom report to Desoer.

In an interview, Desoer said that the reorganization combined activities that were being duplicated and also clarified employees' responsibilities. "It's been very well received," said Desoer, who spent 35 years at Bank of America before joining Citi.

Another part of the bank that came into Desoer's orbit following a rocky period is Citi's stress-testing operations.

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Citi had failed the Federal Reserve's big-bank stress testing exercise — known as the Comprehensive Capital Analysis and Review — in both 2012 and 2014. Desoer took over for the 2016 tests, and Citi has passed in each of the last two years.

Desoer said that the stress tests have become more than a regulatory compliance exercise. The statistical models developed to estimate how well the bank would weather economic distress are also being used to evaluate the risks associated with specific business decisions.

"We take that into consideration with all the other risks, as we're making decisions about an acquisition of a portfolio or an expansion of a business," she said.