Cargill Inc. said Friday that Chief Financial Officer Sergio Rial will resign his post after only 16 months in the job, effective at the end of November, and return to his native Brazil for "personal reasons."

Rial, 52, has also been a member of Cargill's board of directors since 2010, and he holds other positions with the firm. He joined the Minnetonka-based agribusiness giant in 2004 as a leader of its group of food businesses.

Cargill, where sudden exits of top executives are unusual, wouldn't elaborate on Rial's reasons for leaving. Asked whether Rial was terminated or asked to resign, Cargill spokeswoman Lori Johnson said no.

His departure "is tied to a desire to return home," she said.

Rial became a senior vice president and a member of Cargill's leadership team in 2009, when he also became a leader of Cargill's financial services business.

"Since joining us in 2004, Sergio has energized our growth in Latin America and provided vigorous and thoughtful leadership as a member of Cargill's leadership team and board of directors and as chief financial officer," Cargill CEO Greg Page said in a statement.

Rial was CFO during a tough fiscal year at Cargill, one of the world's largest privately held companies.

European financial uncertainties hurt trading operations, while cyclical downturns squeezed its beef and soybean processing businesses. Cargill posted its weakest annual profit since 2003 -- $1.17 billion -- though the company bounced back during its fiscal first quarter for 2013.

While CFO, Rial continued to serve as a leader of Cargill's food and ingredients and financial services businesses. Cargill's major businesses have leadership "platforms" made up of three to five senior executives.

Rial also was Cargill's regional director for Latin America and executive chairman of CarVal Investors, a money management subsidiary. Before joining Cargill, he was a top executive at Bear Stearns in New York, and spent 17 years before that at ABN Amro, another investment bank.

Cargill Chief Operating Officer David MacLennan will serve as the company's interim chief financial officer until Cargill's board selects Rial's successor. MacLennan, who was Cargill's CFO from 2008 to 2011, will continue as Cargill's COO and president.

Mike Hughlett • 612-673-7003