SAN FRANCISCO — Google Inc. has been on a losing streak in its fight to keep customer data stored on overseas servers out of reach from U.S. law enforcement authorities.

Last week, a federal magistrate judge in San Francisco denied Google’s attempt to quash a warrant seeking data stored abroad. It was at least the third such decision involving Google in as many months, and another magistrate judge in Florida in early April forced Yahoo to hand over data in a similar ruling.