World No. 1 men's tennis player Nojak Djokovic reportedly purchased an 80 percent stake in Danish biotech firm QuantBioRes, which is looking for a treatment for COVID-19, in June 2020.
QuantBioRes CEO Ivan Loncarevic revealed the news to Reuters' Nikolaj Skydsgaard but declined to say how much Djokovic paid for the stake.
The report comes three days after Djokovic was forced to leave Australia after the country's federal court upheld Immigration Minister Alex Hawke's decision to cancel the unvaccinated tennis star's visa.
Travelers must provide proof of COVID-19 vaccination to travel to and from Australia. Djokovic was looking to compete in the Australian Open under a medical exemption.
The Chief Medical Officer of Tennis Australia told Djokovic in a letter Dec. 30 that he had received a medical exemption to travel to Australia and compete in the tournament, per CNN's Hannah Ritchie.
A document from Australia's Federal Circuit Court revealed that Djokovic received the exemption on the grounds that he had recently recovered from COVID-19, for which the Serbian tested positive Dec. 16.
However, the visa was canceled one week later under the Migration Act, which "allows for the cancellation of a visa where the holder poses a risk to the health, safety or good order of the Australian community, or to an individual within the Australian community."
Djokovic took the matter to court, and on Jan. 10, Australian Federal Judge Anthony Kelly overruled the visa cancellation decision, allowing him to play.
"Judge Kelly made points in Djokovic's defense Monday, demanding to know what more the athlete could have done to meet Australia's entry requirements," CNBC's Natasha Turak wrote.
"The government on Monday acknowledged that it did not give Djokovic and his team sufficient time to react after informing him of his visa cancellation."
Hawke then made the decision to cancel Djokovic's visa. After the star lost his appeal, the 34-year-old's quest to win his fourth straight Australian Open (and men's singles record 21st Grand Slam title) was over before it began.
Salvatore Caruso replaced Djokovic in the draw as a lucky loser. He fell in straight sets to Miomir Kecmanovic, who was previously scheduled to face the defending champion.
Kecmanovic has since defeated Tommy Paul in straight sets in the second round, and now he'll take on No. 25 Lorenzo Sonego in the third round.