The U.S. Securities and Exchange Commission announced that it has decided to conduct a formal investigation into London-based Royal/Dutch Shell Group‘s surprise announcement on Jan. 9 that it was downgrading 20 percent of its proved reserves and reclassifying them into less certain unproved categories. The SEC had been making an informal inquiry into the matter since Shell’s announcement. A formal investigation usually means that SEC regulators have reason to believe laws may have been broken, but do not have sufficient evidence to make that conclusion. The investigation gives the SEC legal power to subpoena documents and testimony from Shell.