UBM, the parent company which agreed to sell PR Newswire to Cision last month for $841M, said that federal regulators have asked for information about "certain PRN products."

UBM said the sale is now expected to close after the first quarter after initially planning for a close before the end of Q1.

The company said the US Department of Justice requested "additional information and documentary material ... relating to certain PRN products which account for a very small portion of PRN's global revenues."

UBM and Cision are both cooperating fully with the DOJ requests, said a statement.

"Both parties remain confident that completion will be achived," they said.