China's National Development and Reform Commission (NDRC) on Wednesday confirmed that it has been probing Qualcomm and InterDigital.
The anti-monopoly investigation into Qualcomm follows complaints from groups that alleged the U.S. company had been abusing its chip market dominance to charge higher fees, said Xu Kunlin, the head of NDRC's pricing supervision and anti-monopoly bureau.
Earlier this month, the China Mobile Communications Industry Association said it had filed a complaint against Qualcomm for overcharging for use of its patents.
The NDRC confirmed it conducted raids at Qualcomm's Beijing headquarters and at its Shanghai offices in November.
Qualcomm said the company was cooperating with the investigation.
Under the Chinese anti-monopoly law, the NDRC can impose fines of between 1 and 10 percent of a company's revenues for the previous year.
The commission last year also launched an anti-monopoly investigation into InterDigital, a U.S. company that holds patents related to wireless devices and networks. Complaints were made that the company has been overcharging its clients over patent licensing, according to the NDRC.
The Chinese regulator said that InterDigital has agreed to certain commitments and that it would further study the case.