As full funding for Affordable Connectivity Program expires, FCC Chairwoman Rosenworcel issues letter to lawmakers.
That makes 10 open challenge windows, plus 18 states finished with the first phase of the process.
The legacy copper provider has secured 25% market share in fiber-based broadband services.
A U.S. senator, FCC commissioners, and a White House official rallied alongside public interest and industry groups for the subsidy program.