China’s ByteDance-owned TikTok has secured a major new office sublease in San Jose, signaling continued expansion in Silicon Valley even as it faces a potential U.S. ban over national security concerns.

According to documents filed on March 19 with the Santa Clara County Recorder’s Office, TikTok has subleased a 162,600 square-foot office building at 1143 Coleman Ave in the Coleman Highline tech campus. The building was previously leased by streaming device maker Roku, which downsized its footprint last year, SilliconValley.com reports.

The deal comes just months after ByteDance took over a massive 658,000-square-foot office complex nearby at 1193 and 1199 Coleman Ave through a sublease from Yahoo. Between the two sites, TikTok and its parent company now occupy over 820,000 square feet in the area – enough for potentially 3,200-4,100 workers.

TikTok is actively preparing the interiors of the newly leased 1143 Coleman building for occupancy, with “certain tenant improvements” underway, per county records. A specific move-in timeline remains undisclosed.

The expansion defies concerns over TikTok’s Chinese ownership and allegations that the app represents a national security risk by potentially allowing data harvesting and censorship influenced by Beijing. Congress and the Biden administration are investing efforts to ban the app over these issues.

Despite the potential ban, TikTok continues rapidly growing its real estate footprint in Silicon Valley. In 2021, ByteDance’s corporate offices at 1193 and 1199 Coleman were acquired for $780 million by London investment firm AGC Equity Partners.

The new 1143 Coleman lease deal also injects life into San Jose’s struggling office market. Commercial real estate giant Blackstone purchased that building, an amenities center, a parking garage, and two other offices for $275 million in 2020 as part of the Coleman Highline development across from the airport.

With major tech tenants like Yahoo, Roku, and now TikTok taking over millions of square feet, all buildings in the mixed-use campus remain income-producing despite some shuffling of occupants. This provides a rare bright spot for Silicon Valley landlords grappling with high vacancies.

TikTok’s expansion raises questions about its long-term U.S. viability if controversies over its Beijing ties ultimately lead to a nationwide ban. But for now, the social media company is undeterred, building out a major new operational hub in the heart of Silicon Valley.