The 64-year-old said that it was "very possible" that he could be forced to sell his share of the club in the summer.
Mandaric made his fortune by investing in technology shares, but the stock market crash has cost him £60million on top of his £20million investment in Pompey.
"I've probably lost three times what I've invested in Pompey," said Mandaric.
"But I'm not crying. I'm happy. I'm getting my rewards seeing Pompey do so well this season.
"I've no regrets. I want to go forward for our fantastic fans, and execute everything I said I would to get us to the Premiership," he told the club's website.