Only two days after Exxon Mobil Corp. reported the highest annual earnings of any company in U.S. history, some prominent lawmakers are asking whether it’s time to break up oil conglomerates formed through mega-mergers in the past several years.

“We have seen extraordinary concentration in the energy industry. We’ve had a string of consolidations which are really staggering,” said Sen. Arlen Specter, R-Pa. “I am somewhere between impressed and astounded by these profits, and it raises big questions about whether something needs to be done in the merger and acquisitions field,” he said.