The Serbian star holds an 80 per cent stake in Danish biotech company QuantBioRes, Reuters reports.
The company’s chief executive Ivan Loncarevic said Djokovic acquired the controlling stake in June 2020 but refused to say how much it was.
It involves producing a a peptide, which curbs the coronavirus from infecting the human cell.
The project involves 11 researchers in Australia, Denmark and Slovenia. The company expects to launch clinical trials in the UK this northern summer.
According to the Danish company register, Djokovic and his wife Jelena own 40.8 per cent and 39.2 per cent of QuantBioRes, respectively.
Djokovic is listed by Forbes in the world’s top-50 highest paid athletes for 2021. It calculated his on-court earnings at $6.2 million, significantly less than the $41 million he earned off the tennis court.
Djokovic’s legal bid to play in the Australian Open ended on Sunday when the Federal Court dismissed his appeal against Immigration Minister Alex Hawke’s decision to cancel his visa.
Djokovic’s most pressing concern is the next grand slam – the French Open in May – after authorities said on Monday there would be no exemption from a new vaccine pass law.