Turnover has long been been a hallmark of the top finance job, and 2007 was no exception. The 2,313 CFO changes at public companies marked just a slight increase from 2006’s rate, but reshaped the executive suites of some of the country’s best-known businesses. Pfizer, Citigroup, and McDonald’s — corporate titans with a combined market capitalization of more than $370 billion — were just three of the companies that replaced their CFOs in 2007, according to research firm Liberum, which tracks management changes at U.S. and Canadian public companies. In the Fortune 1,000 alone, 181 new finance heads were named, according to recruiter Heidrick & Struggles.

“The pressure on CFOs is so intense, and it is coming from shareholders, CEOs, and boards,” says Richard Jacovitz, senior vice president and director of research at Liberum. The declining economy just makes matters worse.

A wide range of factors make the top finance seat an uncomfortable one these days. Some turnover is related to backdating, Securities and Exchange Commission investigations, and restatements. But even as compliance issues recede, CFOs also face new demands. Boards are once again asking finance executives to turn their attention to driving profitability and strategic direction, says Joel von Ranson, a consultant in the financial officer practice at executive recruiter Spencer Stuart in New York. “Boards are demanding a higher and higher level of CFO performance on planning and the strategic positioning of the company, whether that’s through leading acquisitions or controlling the cost base,” he says.

“Companies always want to upgrade the CFO position,” says John Wilson, president and CEO of San Francisco–based recruiting firm J.C. Wilson Associates. “The current job holder is at risk even if a company is doing well, because at some point the board begins to get nervous about whether the sitting CFO has the skill set to take it to the next level.”

The merger-and-acquisition boom of the last few years has also prompted changes in the top finance spot, says Wilson. “So many tech companies were acquired in 2007 that it’s very typical to talk to a CFO who is between jobs because his company was acquired,” he says.

Some More Volatile than Others

Some industries were particularly volatile for CFOs last year. In pharmaceuticals, for example, Pfizer, Merck, Wyeth, Astra Zeneca, Johnson & Johnson, and Amgen all found new finance chiefs in 2007.

Michele Heid, managing partner at Heidrick & Struggles in Philadelphia, sees those changes as part of a natural progression. “That’s a sector where there had been a lot of continuity for some time,” she says. “People had been in those roles for a long time, and the competitive environment and the regulatory environment in the pharmaceutical industry make for a lot of wear and tear on the CFO.” Former Merck CFO Judy Lewent, for example, had been with the drugmaker for 27 years, 17 as finance chief.

According to Liberum, the drug and biotechnology sector experienced more finance-executive changes last year — 203 — than any other industry. The energy industry and the metals and mining sector also had significant turnover, with 156 and 140 CFO changes, respectively. Banking, which has been battered by the subprime-mortgage crisis, saw CFOs depart from Morgan Stanley, Merrill Lynch, and U.S. Bancorp, along with Citigroup (see “Missing Pieces“). The industry had 115 finance-chief changes overall. Some CFO departures have a domino effect; when Gary Crittenden replaced Sally Krawcheck as finance chief at Citigroup, he left an open CFO position at American Express.

Of course, this is not all bad news for the CFOs concerned. Liberum’s data shows that 20 percent of finance-executive changes last year were promotions. Intel’s longtime finance chief, Andy Bryant, for example, moved up the corporate ladder into a newly created chief administrative officer role in which he oversees finance, human resources, IT, and E-business worldwide for the semiconductor manufacturer.

CFOs are jumping jobs of their own accord, too, says Heid. “There is a lot of movement because private-equity firms are attracting people from public companies and actively recruiting them to run portfolio companies,” she says.

Wilson agrees that many finance chiefs are searching for new opportunities, often seeking to add operational experience to their résumés. “Now that there is a greater familiarity with the regulatory requirements of Sarbanes-Oxley, CFOs have time to think more broadly about where they are taking their careers,” he says. Some are aiming for chief operating officer or chief executive jobs.

Jacovitz predicts continued high turnover among finance chiefs in 2008; in January alone, Liberum reported 195 CFO changes. Heidrick & Struggles reports 17 new CFO openings in the Fortune 1,000 in January. On the bright side: “It’s still not quite as high as CEO turnover,” Jacovitz says.

Kate O’Sullivan is a senior writer at CFO.