Giannis Antetokounmpo of the Milwaukee Bucks announced on Friday that he has joined prediction market Kalshi as a shareholder, making him the first NBA player to invest directly in the company.

“The internet is full of opinions. I decided it was time to make my own,” said the two-time NBA MVP. in a social media post. “Today, I joined Kalshi as a shareholder. We are all in Kalshi now.”

The announcement did not go down well on social media. On Redditfor example, one user described it as “literally a conflict of interest,” while another described Kalshi as “cancer” and another wondered, “is this allowed.”

According to The Athleticthe NBA’s recent collective bargaining agreement allows players to advertise and take bets of up to 1% on sports betting companies, as long as they don’t promote league-related bets.

Kalshi said it will work with Antetokounmpo on marketing and live events — and in accordance with the company’s “strict terms of service prohibiting insider trading and market manipulation,” he will not be allowed to trade in NBA-related markets.