Is bitcoin being manipulated? A professor who proved it in 2017 sees more red flags.

• In 2017, professor John Griffin noticed the price of bitcoin appeared to be propped up by a single "whale," and he's now seeing similar red flags, per Fortune.
• At the end of 2022, Griffin observed that bitcoin seemed to bounce each time it breached the $16,000 floor.

After a dismal outing last year, bitcoin has skyrocketed more than 40% to start the new year. But John Griffin, a finance professor at the University of Texas McCombs School of Business, thinks there's something suspicious going on, according to Fortune.

He had a similar inkling of foul play in 2017, when he and a colleague noticed that a single bitcoin "whale" seemed to drive the token's price and distort trading.

In 2018, Griffin and Amin Shams published a 118-page report that detailed their proof of bitcoin market manipulation by a single entity. Two years later, the report was picked up by the peer-reviewed Journal of Finance.

Today, he sees parallels.

"It's very suspicious," Griffin told Fortune. "The same mechanism we saw in 2017 could be at play now in the still unreal bitcoin market."

He explained that a token manipulator would want to set a floor price for their asset, which seems to be the case now for bitcoin, which typically sees high volatility rather than stability.

"In a period of highly negative sentiment, we've seen suspiciously solid floors under bitcoin," he said.

Griffin maintained that the sheer size of the crypto market and the amount of data has made definitive proof elusive. Not only that, but he said bad actors are sophisticated enough to hide their identities.

Still, one finding from Griffin's research five years ago was that sizable bitcoin purchases happened when the token reached certain thresholds.

"We saw far more purchases at those benchmarks," Griffin said. "The whale kept establishing price floors, and those floors kept rising. It wasn't a club. It was one entity. But when the whale held the price at the thresholds, that made it look as if bitcoin was safe at those floors. That made it look safe for funds and small customers to buy bitcoin, driving the price still higher."

Bitcoin price floor manipulation

During bitcoin's latest run, it's peculiar how reliably bitcoin bounced above $16,000 seemingly the moment it breached that level, he said. That dynamic was evident when Sam Bankman-Fried's FTX was crashing.

In a five-day stretch in November, bitcoin plunged 25% to $15,900. Then, according to Fortune calculations, the token traded between $16,000 to $18,000 every single day leading up to January 11 except for one.

For bitcoin to exhibit that degree of stability is unusual. FTX marked one of the largest collapses in crypto and financial history, yet the price of the world's largest token saw some of the smallest swings ever.

Today, Griffin believes that bitcoin remains "highly vulnerable to manipulation," per Fortune.

"We don't have concrete analysis this time," he added. "The truth may emerge in specific stories, if there is collusion."