General Motors Co.’s new executive lineup sparked speculation Tuesday about who would succeed Dan Ammann as chief financial officer.<br /><br />Mr. Ammann was named president, in charge of GM’s regional operations around the world, as well as the Chevrolet and Cadillac brands and GM Financial. He will remain CFO through mid-February when the company reports its year-end financial results.<br /><br />At the top of the short list to replace him is Chuck Stevens, CFO of GM’s North American division since 2010, according to two people close to the vetting process.<br /><br />Mr. Stevens has had a long, international career at GM, including the CFO post in South America. And the company has recently been raising his profile. In August, he represented GM at the J.P. Morgan Automotive Conference in New York, and he fielded analysts’ questions during GM’s third quarter earnings call.<br /><br />“We’re not feeding the speculation here or going beyond what was included in the press release,” wrote Dave Roman, a GM spokesman, in an email.<br /><br />Mr. Ammann, who is 41, is a former investment banker with Morgan Stanley and Credit Suisse. He was on board in 2010 to help take GM public as part of its financial separation from the U.S. government, which sunk almost $50 billion into the company to keep it from failing.<br /><br />“For an outsider to have a shot at the CFO role at GM, they would need to have a global background in a best-in-class finance organization,” said Christopher Langhoff, founder and managing partner of CCL Search LLC, an executive search firm that specializes in placing CFOs. “They are likely to have come up the analytical side of finance and have some solid experience with The Street both in terms of investor relations and balance sheet management. And…they would have to be ‘big enough’ to help retain and attract the talent that the organization needs to continue their recovery.”<br /><br />In The Wall Street Journal’s CFO Journal last Friday, Mr. Ammann,  wrote about how he transformed GM’s finance organization. He put in place a “fortress balance sheet,” with ample liquidity and little debt so the company can reinvest in the business, regardless of the business cycle.<br /><br />Under Mr. Ammann, GM also reduced its U.S. salaried pension obligation by $28 billion in a pension transfer transaction, more than doubled its revolving credit line to $11 billion, executed a $4.5 billion bond refinancing and secured an investment grade credit rating.<br /><br />GM’s finance department employs 4,600 people globally, and Mr. Ammann wrote, “Our finance leadership team has evolved to play a much more proactive role in running the business alongside their operating management partners. A central objective of the finance team is to help drive better business decisions. To do this we need to bring high quality information and insights to the table.”<br /><br />Nevertheless, whoever fills Mr. Ammann’s shoes will face some formidable challenges. The company needs to improve the operating margins on its vehicles, beef up its sales of small cars and improve the fuel efficiency of its trucks.<br /><br />“The most obvious challenge is pricing pressure,” said Michael Schmall, a managing partner for The Planning Edge, an automotive market research and consulting firm. “GM needs to make more money per vehicle.”<br /><br />Mr. Stevens acknowledged that in an August conference call. He said the company is focused on material and logistics costs, quality and building the brand.<br /><br />“My primary role is to make sure that North America is as profitable as possible so that we continue to and improve our cash flow generation for the corporation,” he said, according to a transcript provided by FactSet.<br /><br />William Selesky, who follows GM for Argus Research and has met Mr. Stevens, said he would view Mr.’s Steven’s appointment as company CFO as a positive. The pressure will be on, however, if Mr. Stevens can’t quickly boost operating margins and close the gap with rival Ford Motor Co. “They’re going to start giving him a hard time [otherwise].”