The two firms operating the nation’s largest part-time job portals, Albamon and Alba Heaven, were fined 2.6 billion won ($2 million) for collusion, the antitrust watchdog said Monday.

Following a record 16.4 percent minimum wage hike in 2018, JobKorea and MediaWill Networks, which run Albamon and Alba Heaven, respectively, colluded with each other to reduce the type of jobs available in free job postings. They also increased and fixed the price of paid services in order to steer users toward paid postings and maximize their profits on both platforms, according to the Fair Trade Commission.

JobKorea has to pay 1.6 billion won and MediaWill Networks 1 billion won, the FTC said.

The watchdog noted that the collusion occurred when the pay hike strained small- and medium-sized firms and the part-time job market.

Albamon and Alba were the top two job portal platforms in 2019, with 2.4 million and 2.1 million monthly users, according to market tracker IGAworks. The commission described them as a duopoly in the part-time job market, saying they abused their market dominance by colluding with each other.

The FTC investigation revealed that the collusion was prompted by a competitive concern that if one platform shifted to paid services or raised the price independently, it could risk losing users to the other.

“This case is significant as it marks the first time that the FTC has penalized online platform operators for collusion in limiting free-of-charge services and encouraging paid conversions,” the FTC said in a statement.

“It sets the precedent that such collusion also constitutes a violation of the law.”

As of this year, the two still are the most used job portal platforms in Korea, IGAworks data showed. Albamon has a monthly user base of 2.2 million, and Alba with 1.9 million.