Hong Kong stocks were back in negative territory on Thursday, erasing most gains from the previous session, as investors struggled to maintain upward momentum amid weak global cues.

The Hang Seng Index fell 1.2%, or 236.17 points, to close at 19,366.96. The Hang Seng China Enterprises Index retreated 1.5%, or 102.89 points, to end at 6,924.51.

While the market is optimistic about Beijing introducing more stimulus measures, investors have "increased concerns and frustrations" over the prospect of additional US tariffs on Chinese goods, Winnie Wu, China equity strategist for Bank of America Securities, told Bloomberg Television.

US President-elect Donald Trump plans to impose new anti-drug tariffs on China on the first day of his second term, which begins on Jan. 20, 2025.

Trump said he would levy an additional 10% on Chinese products entering the US, a move aimed at boosting border security and curbing drug shipments to the US.

Shares of BYD (HKG:1211, SHE:002594) closed nearly 3% lower on Thursday after the carmaker asked suppliers to lower their prices amid the escalating price war in China's vehicle market.

Other HSI heavyweights also ended lower. Meituan (HKG:3690) led decliners with an over 2% fall, followed by Alibaba Group (HKG:9988) and Xiaomi (HKG:1810).

In corporate news, Hangzhou Jiuyuan Gene Engineering (HKG:2566) slumped in its trading debut. The biotech firm closed at HK$7.65 per share, down over 38% from its IPO price of HK$12.42.