Investors fear they may be $387m (£254m) in the red after a Hong Kong Bitcoin biz fell silent.
The investment and trading website MyCoin reportedly closed its Kowloon offices a few weeks ago, and the company has not yet responded to inquiries from The Reg and other publications.
According to the South China Morning Post, MyCoin had been aggressively flogging Bitcoin "contracts" to investors in East Asia with promises of big payouts.
The idea is you buy a bunch of contracts for, say, $260,000 and get $400,000 back, eventually. We're not quite sure how that'll work, although we gotta point out that the price of BTC (once as high as $1,120 per Bitcoin in 2013) has fallen from about $650 per Bitcoin this time last year to $218 at time of writing.
MyCoin holds as much as HK$3bn ($387m) in 3,000 customer accounts, we're told, with individual investors reportedly standing to be out of pocket as much as HK$50m ($6.45m) if the biz truly has died.
Some customers claim they were told that if they wanted to bring about their promised returns on investment, they should recruit other investors to pump additional funds into the operation.
Should MyCoin not speak up and explain where the money is, a criminal complaint against the firm could be filed as early as Wednesday.
The South China Morning Post reports that back in November, the sole director of MyCoin's parent company resigned and transferred his shares to a company based in the British Virgin Islands.
One month later, the exchange blocked users from withdrawing their money unless they signed up new investors.
If indeed MyCoin is kaput and the investor funds cannot be found and returned, the loss would be the biggest associated with Bitcoin since the 2014 collapse of the Mt. Gox exchange. ®