The White House is “working diligently” to appoint a permanent privacy referee at the State Department to keep in place a trans-Atlantic data transfer pact, a U.S. official said.

The U.S. is making progress toward permanently filling that role as promised, James M. Sullivan, deputy assistant secretary for services at the U.S. Department of Commerce, told reporters on a Dec. 20 call.

“We are working very diligently. The White House is working very diligently on nominating someone for the under...