Only a day after writing that bitcoin had reached new highs in the $360s, the currency slammed through the $400s up to $425 before investors took profits, sending the price dropping back to $385. The gap between the Chinese and American exchanges widened to $23.

The last time the price of bitcoin was above $400 was back in November 2014.

Amidst the conversation about the price rising, eclipsing previous 52-week highs, is a desire to justify the price appreciation. According to Jack Liu of OKCoin, one of the drivers has been a desire for “mainland [China] speculators to move to other assets after the stock market fallout.”

However, another possibility is that some of the Bitcoin demand has been driven by a large MMM Ponzi scheme, according to several Chinese exchanges.

On October 15th, BTCC tweeted out a warning that there might be certain investments being offered to individuals that were not entirely legitimate.

1/ We’ve had reports of dubious “investments” involving #bitcoin. These may be ponzi schemes designed to steal your bitcoins.

1/ We've had reports of dubious "investments" involving #bitcoin. These may be ponzi schemes designed to steal your bitcoins. — BTCC (@YourBTCC) October 14, 2015

Bitcoin Magazine reached out to the three primary Chinese exchanges—Huobi, OKCoin, and BTCC—for comment regarding this warning. Huobi provided the following statement:

“We believe that most of the investors hold a positive attitude towards the future development of bitcoin industry. However, money is neutral. Capital flow is the reflection of the market movement. We can’t deny that MMM to a certain extent pushed the recent spike of bitcoin price. The new investment model of MMM attracted a lot of investors, however it is unsustainable,” said Astrid Tao, Operation & International Marketing Manager at Huobi.

Tao went on to say that, “From the viewpoint of an exchange platform, it’s hard to tell the purpose and reason why they invest in bitcoin. But we’ll do our best to lead these new investors to rediscover bitcoin and the industry, and to guide them to participate in trading in a right way.”

MMM was an organization that ran the world’s largest Ponzi scheme in the 1990s. The founder, Sergei Mavrodi, is believed to have defrauded anywhere from 5 to 40 million people in the amount of $40 billion.

The Mail & Guardian reported on a MMM scheme taking place in South Africa utilizing bitcoin as the means of transferring value. However, those that have participated don’t view it as an investment, but rather, a donation.

“I don’t know exactly how it works, but I am not making an investment, “ Kgomotso (not his real name) told Mail & Guardian. “I am just donating money to somebody, and then somebody will donate to me. People talk ‘investment’, but this is us helping each other.”

In essence, a user who signed up to the MMM today would purchase bitcoin to give to members who signed up yesterday. All along, the user who signed up today would hope that users would sign up tomorrow to give them bitcoin.

Bitcoin Magazine has reached out to BTCC and OKCoin for comment on the MMM Ponzi scheme and will update this piece as more information is available.

Jacob Donnelly is a full-time product manager and freelance journalist covering stocks, business and bitcoin. He runs a weekly digital currency and blockchain newsletter called Crypto Brief.