Alibaba Group might be teed up for the biggest IPO in U.S. history, but so far, its Silicon Valley footprint isn’t very significant.

That could be changing. For years, the Hangzhou, China-based e-commerce giant has had a modest office at Santa Clara Towers. Recently, Alibaba signed a lease for 20,000 to 25,000 square feet or so farther up the Peninsula, at 400 S. El Camino Real in San Mateo, according to numerous industry insiders.

That’s not huge by any stretch of the imagination, but it’s a 200 percent jump over Alibaba’s current 8,000-square-foot suite at Shorenstein’s 3945 Freedom Circle, which is currently being marketed for lease. (And a far cry from the company’s first lease in the Valley, which was for 1,000 square feet in Newark.) The new space could support more than 100 employees, assuming a space ratio of 200 square feet per worker.

And local brokers expect that footprint could expand given the penchant for newly IPO’ed companies to go big. Recent examples of big space grabs coming shortly before or after successful offerings include Rocket Fuel, Gigamon and Arista Networks.

Of course, Alibaba is not based here, but other China-based companies have found the Valley an important part of their R&D operations. The largest presence of a China-based firm here is Shenzhen-based Huawei, the giant telecom company, which has about 250,000 square feet in Santa Clara. Shenzhen-based gaming company Tencent and Beijing-based search engine Baidu also have offices here.

Alibaba’s new space is in a high-rise near downtown San Mateo close to Caltrain. Paul McCann, a managing director for Ritchie Commercial who represents a neighboring office tower, said more tech tenants are shopping the submarket. They’re looking for large floorplates such as his building and 400 S. El Camino, but there’s not a lot of vacancy in the area for when they grow out of the available space.

“It’s great office space because it’s close to all the restaurants and Caltrain,” he said.