House Republicans are demanding information from wireless carriers, including AT&T Inc. and Verizon Communications Inc., about their handling of subscribers’ geolocation data.

House Energy and Commerce Committee ranking member Greg Walden (R-Ore.) and three other GOP committee members sent letters to T-Mobile US Inc., AT&T, Sprint Corp., and Verizon asking about the companies’ privacy policies concerning location-based information and services. The lawmakers also sent letters to Zumigo Inc., a location services company, and Microbilt Corp., a credit reporting company.

The queries follow a Jan. 8 Motherboard report that T-Mobile, Sprint, and AT&T were collecting and selling consumers’ real-time location data to Zumigo, which sold that data to Microbilt.

“This practice of selling and sharing of location information through multiple entities potentially impacts hundreds of millions of American customers,” Walden, and Reps. Bob Latta (R-Ohio), Cathy McMorris Rodgers (R-Wash.), and Brett Guthrie (R-Ky.), said in a statement. “We are deeply troubled because it is not the first time we have received reports and information about the sharing of mobile users’ location information involving a number of parties who may have misused personally identifiable information.”

The lawmakers asked Zumigo and Microbilt to name all U.S. and foreign wireless carriers with which it has commercial relationships, and other questions about how they use consumers’ location data. Questions for carriers include which third parties they have shared location data with since 2007.

A Sprint spokeswoman declined to comment. Spokespersons for Zumigo, Microbilt, T-Mobile, AT&T, and Verizon didn’t immediately respond to requests for comment.