23 of 44
23. Christa Davies
CFO, Aon
Age: 39
Rank change: New
Industry: Finance

After working at McKinsey and attending Harvard Business School as a Fulbright scholar, Davies found her calling at Microsoft, where she rose to be CFO of its platform and services division. In 2007 she joined Aon, the world's largest insurance broker, and has orchestrated its biggest deals ever, including its $5 billion acquisition of Hewitt Associates this summer -- all without losing Aon's strong credit rating.

Opportunist: Last year Davies helped Aon replace AIG as Manchester United's top sponsor through 2014.

NEXT: 24. Lorenzo Simonelli
Last updated October 14 2010: 1:25 PM ET
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