A rally that had seen shares of Altria Group Inc. (NYSE: MO) soar almost 30% this year through Friday suffered a setback on Monday. Shares of the Marlboro maker plunged 6.2%, the biggest slump since March 2020, following a report in the Wall Street Journal that the U.S. government is considering a rule that would lower the nicotine content of cigarettes. The Food & Drug Administration declined to comment on the report and Altria didn’t immediately respond to an email request.