Naver and Kakao, Korea’s two largest online service providers, saw their market caps shrink 7 trillion won each ($5.8 billion) for the last two weeks amid persistent market fluctuations over a potential rate hike by the US Federal Reserve and growing uncertainty over their growth and management ethics.

The US Fed has hinted that it will reduce its overall asset holdings sooner than expected because of unabated inflation. But the hike speculation, which is dragging down shares of Naver and Kakao –- now valued at 55 trillion won and 43 trillion won, respectively -– is not the only hurdle facing the two tech giants.

Signs of stronger regulatory oversight have added to the concern as regulators have openly distanced themselves from the tech giants, vowing to “level the playing field” for internet firms and financial companies.

“We will help tech firms expand fintech services as long as they bring about innovation and better competition. But we will make sure regulations are in place to protect financial stability and consumers,” Koh Seung-beom, chief of the Financial Service Commission, said.

Critics have accused the top financial policymaker and other financial authorities of being soft on tech companies looking to expand and take over financial services dominated by local banks and insurance companies.

Meanwhile, Kakao is facing backlash from investors over one of its senior executives at Kakao Pay, who has “made off” with billions of won in a stock selloff investors say was unethical.

Ryu Young-joon, CEO of Kakao’s payment subsidiary, shed 90 billion won in shares in December, a month after the company went public. The selloff led to a stock plunge to 148,500 won from 208,500 won as of Monday.

Ryu, who was named to head the Kakao group, has offered to resign from the nomination, though Kakao Pay has said that he will complete his term as CEO at the subsidiary until March.