The nation’s four largest wireless carriers have stopped or nearly stopped selling access to subscribers’ real-time location data to third-party data brokers, amid an ongoing Federal Communications Commission probe into their data-sharing practices.

AT&T Inc., Sprint Corp., T-Mobile US Inc., and Verizon Communications Inc. said they’ve moved to stop selling their customers’ location data to location aggregation companies, in letters to Democratic FCC Commissioner Jessica Rosenworcel. AT&T, T-Mobile, and Verizon said they’ve stopped contracting with location aggregators. Sprint said it’s only currently using one location aggregator for limited services, and plans to stop contracting with any aggregators by May 31....