Sean Stein, the president of the U.S.-China Business Council, said that if more information did not emerge soon in the Wells Fargo case, other American businesses might also discourage their executives from going to China.

“In cases like this, transparency is extremely important, or else there will be a spillover effect on other companies’ travel policies,” he said in a telephone interview.

The Wells Fargo executive, Mao Chenyue, was not detained. But she has been ordered not to leave China, according to the bank. “We are closely tracking this situation and working through the appropriate channels so our employee can return to the United States as soon as possible,” Wells Fargo said in a statement.

American businesspeople in China said that they had not heard of any other recent cases like Ms. Mao’s, although there was a flurry of temporary exit bans two years ago. The exit ban on Ms. Mao was first reported by The Wall Street Journal.

Lin Jian, a Foreign Ministry spokesman, said this past week in response to each executive’s case that foreigners were subject to China’s laws while in the country. But he also said on Friday that “we always welcome enterprises from all countries to deepen their engagement in the Chinese market.”