Chinese regulators are investigating several foreign medical device companies over suspicions that they may have bribed hospitals in exchange for sales.

China’s State Administration for Industry and Commerce (SAIC), the agency that oversees market supervision and regulation, and other regulators launched a preliminary investigation last year into the Chinese healthcare units of U.S.-based General Electric, Amsterdam-based Royal Philips, and Germany-based Siemens AG, people familiar with the matter told Bloomberg.

Collectively, these three companies dominate over 80 percent of China’s medical equipment market, Bloomberg reported. Chinese regulators are investigating whether the medical device companies were able to achieve market dominance by bribing hospitals to use their products, the report stated.

So far, no formal investigations have been brought.

As Compliance Week previously reported, Chinese regulators are stepping up enforcement of antitrust laws, resulting in more investigations of U.S. companies. From pharmaceuticals to technology companies to consumer products, no industry seems beyond the reach of China’s aggressive antitrust regime right now, as Chinese authorities continue to crackdown on anti-competitive practices.