The investigation was given the go-ahead by the trade commission's new Chairman William Kovacic, The New York Times reported.
Kovacic's predecessor, Deborah Majoras, who left the commission two months ago, had been blocking a move toward a formal investigation, the Times reported.
Several computer makers and Intel's smaller competitor Advanced Micro Devices, have already received subpoenas in the investigation that follows a Korean Fair Trade Commission fine of more than $25 million announced this week on a ruling that Intel had engaged in a price-fixing there.
Between 2002 and 2005, Intel provided Samsung Electronics and the Tigrem Co. $37 million in rebates in return for their promises not to do business with Advanced Micro Devices, the Korean commission ruled.
The European Commission ruled against Intel last year on similar charges, which claim Intel offers rebates to companies in exchange for limiting or eliminating business with its competitors.