GM's outgoing Southeast Asian chief Martin Apfel with the Chevrolet Miray concept vehicle.

Another experienced executive has elected to quit a senior post with General Motors’ vital overseas operations in a sensitive and fast growing emerging market where GM has been pressing to gain market share.

Martin Apfel, president of GM South East Asia Operations, GM Thailand and Chevrolet Sales Thailand, has elected to leave General Motors, effective July 31, to “pursue other interests”. A permanent replacement will be announced at a later date.

Apfel is the latest in a growing line of senior GM executives, a large share of them working abroad, who have tendered resignations in recent months – or been shown the door.  It’s unclear why so many are exiting at this point, even as GM’s overseas sales gain momentum, but CEO Dan Akerson has made a point of saying that the company will hold its managers more accountable for their work than in decades past.

“I would like to thank Martin for his service to GM,” said GM Vice President Tim Lee, the head of Global Manufacturing and President of the maker’s vast International Operations. “Under his leadership, GM has achieved record sales in ASEAN. We have expanded our manufacturing and sales presence, putting GM in a position for continued growth in this important region. In addition, we have entered new markets such as Cambodia, Laos and Myanmar, while reopening our Bekasi plant in Indonesia,” Lee said

Last month, Susan Docherty, president and managing director of Chevrolet and Cadillac Europe, announced she plans to leave General Motors to “spend time with her family.” The parting is an amiable one, according to GM insiders, who noted that the Canadian-born Docherty will remain at her post until September 30.

(GM Europe manager Docherty unexpectedly resigns. Click Here for that story.)

Nonetheless, the departures of Apfel, Docherty and a string of other senior managers has raised questions about why the revolving door seems to suddenly be spinning faster at GM.

Docherty and Apfel’s resignations follow the promotion of Alan Batey as senior vice president, Global Chevrolet. In his global Chevrolet role, Batey will report to GM Chairman and CEO Dan Akerson. Batey will also serve as the head of U.S. Sales, Service and Marketing for Chevrolet, Buick and GMC, and will report to Mark Reuss, president, GM North America. Batey will also be a member of GM’s Executive Operations Committee.

(Chevy names Batey new global brand boss. Click Here for the story.)

Apfel  began his GM career as an analyst with Adam Opel AG in 1989. He has held several key positions in human resources, labor relations, manufacturing and general management, including managing director of Opel Portugal SA, president of Opel Eisenach GmbH, director of Opel’s Bochum plants, and GM executive director of Global Manufacturing Strategy and Planning. He has been in his present position since March 2, 2010.

His departure comes just days after

GM signed a letter of intent with Pacific Alpine Pte. Ltd for the Chevrolet brand to return to Myanmar, which long had been off limits to outside investors because of human rights violations.  The country’s first Chevrolet showroom is scheduled to open in the fourth quarter.

“This is a significant milestone for Chevrolet’s expansion across Southeast Asia, and signals our commitment to grow in the region. Myanmar has a population of more than 60 million people. With the market and economy opening up, and with the increasing affluence of Myanmar’s people, the potential for growth is very high,” Apfel said earlier this week.

“One of the most-watched sectors in Myanmar is the automotive industry. About 90% of the vehicle population in Myanmar is more than five years old. The change in policy to allow the import of new cars will see a swift response from global and regional players. We want to put our foot in the door before the floodgates open,” added Albert Pang, Managing Director of Pacific Alpine Pte. Ltd.

The Southeast Asian region is another emerging market GM has been hoping to target, though it faces stiff competition from Japanese and other foreign competitors and currently has just a 2.7% regional market share.  Apfel’s successor is almost certain to face severe pressure to ramp up that figure rapidly.