Shares of WuXi AppTec, a leading Chinese biotech company, surged by almost 7% on Wednesday, driven by the company's announcement of a significant share buyback plan despite facing potential headwinds from a controversial U.S. bill targeting Chinese biotech firms.

WuXi AppTec revealed plans to repurchase up to 1 billion yuan ($140.53 million) worth of its A-shares on the Shanghai Stock Exchange within the next three months. The share buyback program is seen as a vote of confidence from the company's management and could boost investor sentiment, contributing to the stock's rally.

However, the company's shares faced pressure on Tuesday after the U.S. House of Representatives passed the Biosecure Act, which aims to restrict business with WuXi AppTec and several other Chinese biotech companies on national security grounds. The bill accuses these companies of collecting genome data, raising concerns about potential trade tensions and regulatory challenges for WuXi AppTec's operations in the U.S. market.

China's Foreign Ministry swiftly condemned the U.S. bill, describing it as "discriminatory" and urging the U.S. to abandon its "ideological bias." Spokesperson Mao Ning stated that China will continue working to protect the rights and interests of Chinese companies and support them in safeguarding their own rights and interests in accordance with the law.

Despite the U.S. bill's potential implications, investors appear to have focused more on WuXi AppTec's share buyback announcement, at least in the short term. The market's reaction suggests that the positive sentiment surrounding the buyback plan outweighed the concerns raised by the Biosecure Act, leading to the stock's surge on Wednesday.