“We are big in China, and we want to be,” said Stefan Jacoby, the president of General Motors International. His division, which officially moved here on Aug. 5, no longer includes the company’s China operations, but encompasses G.M. subsidiaries in Africa, the Middle East, Southeast Asia, Australia and South Korea.

Image Procter & Gamble opened this research center in Singapore, though it remains in China. Credit... Charles Pertwee for The New York Times

The many frustrations of doing business in China have made some difference in the plans to move executives here — choking air pollution, countless regulations that favor local competitors and weak protection for intellectual property. A rising wave of economic nationalism has also manifested itself in large-scale raids on the Chinese offices of multinationals in the automotive, pharmaceutical and technology sectors. Police officials are copying large numbers of computer hard drives and interrogating employees without allowing access to legal advice.

More important, many multinationals are starting to pay renewed attention to Southeast Asia, which is showing signs of revival 17 years after the Asian financial crisis. They have found it hard to do that from Shanghai or Beijing. Each major city has no more than one flight a day to Jakarta, Indonesia, for example. And China’s diplomatic and trade ties to Southeast Asia have been strained by its increasingly assertive claims to control over practically all of the South China Sea.

The reasons for companies to shift headquarters to Singapore, “relate to the growth opportunities in Asia Pacific beyond just China,” said Keat Chuan Yeoh, the managing director of the Economic Development Board, Singapore’s investment promotion agency.

Philipp Rösler, a former vice chancellor of Germany who is now a managing director of the World Economic Forum in Davos, Switzerland, said the forum had been surprised by the number of its member companies that had said in the last several months that they were considering moving their local or regional headquarters out of mainland China.