China Unicom's stock plummeted 5.24% in the pre-market session on Monday, underperforming the broader market.

The sell-off came after a bipartisan US House panel demanded that China Unicom, along with other major Chinese telecom firms, disclose any ties to the Chinese government and military by March 31st. The lawmakers cited concerns over potential national security risks linked to the companies' US operations, including cloud services and routing of internet traffic, which could enable espionage or unauthorized data access by Beijing.

The intensified scrutiny follows major cyberattacks that compromised American telecom infrastructure, raising alarms about the threats posed by Chinese telecoms with alleged government links. While the Federal Communications Commission has previously restricted these firms' operations, they can still provide cloud services and route US internet traffic, according to reports.