Google Fiber, which is working on providing a broadband alternative in a dozen U.S. cities, has filed a business registration with the Colorado secretary of state.

But the California company denies that any Colorado cities are on its shortlist for expansion.

“We don’t have any current plans to expand to additional cities beyond our current potential Fiber cities. We love that people are excited about Fiber, but we have to start somewhere — we have a lot of work to do before we can talk about additional expansion plans,” Lauren Barriere, a Google spokeswoman, said in an e-mail.

Google Fiber has networks in Austin, Texas; Provo, Utah; and Kansas City, Mo. It is working on networks in Salt Lake City; Nashville, Tenn.; Atlanta; and Charlotte and Raleigh-Durham, N.C.

The company is studying Portland, Ore.; Phoenix; San Antonio; and San Jose, Calif., for future networks.

Last year, Tech Republic Listed Denver among 10 cities it considered on Google Fiber’s short list for expansion. The service targets 1 gigabit speed Internet for homes and small businesses, which is about 10 times the going speed in most cities.

Short of a network, the registration may indicate Google Fiber has plans to locate workers or equipment in the state, but the company isn’t providing any details if that is the case.