China Evergrande Group soared as it returned from a trading halt, driven by what appears to be bets on a penny stock even as the developer’s fate hangs in the balance amid an official probe into its billionaire founder.

The property group’s shares jumped as much as 42% in early Tuesday trade before paring much of the gains. Unit Evergrande Property Services Group Ltd. rose nearly 14% earlier but has since lost over 8%.

Evergrande requested trading resumption from the Hong Kong stock exchange Monday, saying there’s no other pertinent information that needs to be disclosed. Shares in the company and its property services unit were suspended on Thursday, a day after people familiar with the matter said the firm’s founder had been taken away by police.

Analysts caution against reading too much into the unexpected share surge, saying that the ongoing investigation into founder Hui Ka Yan’s suspected crimes and renewed uncertainties about the company’s debt restructuring will continue to weigh on investor sentiment. The developer, which is at the epicenter of China’s property crisis, faces an Oct. 30 Hong Kong court hearing of a petition to liquidate the firm.

“Looks like the gains are driven by speculative money,” Willer Chen, senior research analyst at Forsyth Barr Asia Ltd. “With this volatility, I really don’t know if there’s any chance for any proper investor to make money on this name.”

Evergrande’s crisis entered a new phase after Chinese authorities notified the company last week that chairman Hui Ka Yan has been subject to “mandatory measures” relating to “suspicion of illegal crimes.” The Shenzhen-based firm didn’t elaborate on what the measures entailed or what crimes he is suspected of committing.

Chinese authorities are investigating whether Hui attempted to transfer assets offshore while the company was struggling to complete unfinished projects, the Wall Street Journal reported on Monday, citing unidentified people with knowledge of the matter.

The developer’s debt woes deepened last month after it scrapped key creditor meetings and said it has to revisit a plan to restructure offshore debt. Its dollar bonds remain at deeply distressed levels. Its key mainland unit has recently failed to repay a local bond, while Evergrande said it couldn’t satisfy regulatory requirements to issue new notes.

Read more: Evergrande Drops 87% in Hong Kong After 17-Month Halt, Loss

Evergrande’s trading resumption “will likely fail to ease concerns about regulatory risks for the developer,” said Kristy Hung, a Bloomberg Intelligence analyst. “The regulator’s ban on new bond issuance by Evergrande threatens to scupper its offshore-debt restructuring, heightening the risk of liquidation and raising questions about its capacity to operate as a going concern.”