KEY POINTS
  • "That's not necessarily insider trading or fraud. But it is troubling," says the SEC's Robert Jackson Jr.
  • "I'm asking if the stock is cheap then why is the executive selling into the buyback," he adds.
  • Jackson is seeking an "open comment period" on the agency's buyback rules, which he says have not been touched in 15 years.

Robert Jackson Jr., a commissioner of the Securities and Exchange Commission, is calling out CEOs who authorize stock buybacks and then sell their personal shares during those repurchase programs.

"That's not necessarily insider trading or fraud. But it is troubling because when an executive does a buyback they're suggesting to the market the stock is cheap. I'm asking if the stock is cheap then why is the executive selling into the buyback," Jackson told CNBC's "Squawk Box" on Tuesday. He did not name any executives or companies.