Possesses 5'->3' exoribonuclease activity. Required for the processing of nuclear mRNA, rRNA and small nucleolar RNA (snoRNA) precursors. May promote termination of transcription by RNA polymerase II via the recruitment of 3'-end processing factors to the poly(A) site and by the degradation of nascent RNA downstream of the poly(A) site. Inhibited by nucleoside 3', 5'-bisphosphates. Optimum pH is 8.0-8.8. Interacts with RAI1 and RTT103. Present with 623 molecules/cell in log phase SD medium. Belongs to the 5'-3' exonuclease family. XRN2/RAT1 subfamily.