Shares of General Electric Co. GE, -2.41% turned lower in premarket trade Wednesday, after Chief Financial Officer Jamie Miller said in the industrial conglomerate's post-earnings conference call with analysts that the Securities and Exchange Commission was investigating the process that led to the large insurance reserve increase announced last week, according to a transcript provided by FactSet. Miller said the SEC was also looking into GE's revenue recognition and controls for long-term service agreements. Miller said the company is "cooperating fully" with the investigation, which she said is still in "the very early stages." The stock fell 0.5% in premarket trade, after being up as much as 5% after the company reported fourth-quarter results. The stock has tumbled 22.8% over the past three months through Tuesday, while the Dow Jones Industrial Average DJIA, -0.87% has climbed 10.5%.