Federal regulators have opened an insider trading inquiry on the $23 billion acquisition of H.J. Heinz, according to a published report.

Citing an unnamed source who was briefed on the matter, The New York Times reported Friday that the Securities and Exchange Commission is looking at "unusual trading" surrounding the deal for Heinz to be purchased by Warren Buffett's Berkshire Hathaway and 3G Capital. The report said regulators first noticed a suspicious spike in trading on Wednesday.

A spokeswoman for the SEC, Christina D'Amico, said the agency does not confirm or deny the existence of investigations.

Representatives for Heinz, Berkshire Hathaway and the public relations agency representing 3G and Berkshire in the deal did not immediately return messages seeking comment.