Specialist work at the Barclays post on the floor of the New York Stock Exchange just after the closing bell July 24, 2013 in New York. Barclays' CFO stepped down on August 14, 2013 citing health problems. - 

There's news today that Christopher Lucas, the chief financial officer of the global financial giant Barclays, is stepping down due to health problems. A change in the number three executive spot at a corporation might not always grab headlines, but the person filling that position is vital to a company's structure.

So what happens when a CFO suddenly goes away? Paul Oman is a partner at BOI Consulting, works to provide companies with temporary chief financial officers when they're in a bind.

"We parachute in when a company is in turmoil or transition or just wants to really understand itself better," says Oman. "A lot of times with the CFO position, it's pretty technical. You've got several different types of CFOs -- your strategic guys or your technical accounting guys or your fundraising guys. We can provide people to fit that exact niche that you're looking for so you don't have to rely on that secondary guy who might not be there yet."

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