Bitcoin's epic rise last year may have been more than investor fervor. A study published Wednesday says at least half of the jump in bitcoin was due to coordinated price manipulation.
University of Texas finance professor John Griffin, who has a 10-year track record of spotting financial fraud, and graduate student Amin Shams examined millions of transactions on cryptocurrency exchange Bitfinex. In a 66-page paper, the authors found that tether was used to buy bitcoin at key moments when it was declining, which helped "stabilize and manipulate" the cryptocurrency's price.
"Fraud and manipulation often leave footprints in the data and it's nice to have the blockchain to track things," Griffin told CNBC.
By tracking Bitfinex transactions, which are recorded on a public ledger, Griffin found that another cryptocurrency, tether. was used to buy bitcoin after large price falls. The authors tracked that pattern and found periods of suspicious bitcoin price activity tied to the issuance of tether, which is purportedly pegged to the value of the U.S. dollar.
"It was creating price support for bitcoin, and over the period that we examined, had huge price effects," Griffin said. "Our research would indicate that there are sophisticated people harnessing investor interest for their benefit."
Griffin found that about 87 hours, or about 1 percent, of heavy tether trading could explain 50 percent of the rise of bitcoin, and around 64 percent of the rise of other major cryptocurrencies.
Bitcoin rose to almost $20,000 in December after starting last year below $1,000. This year, the world's first and most popular cryptocurrency has lost more than half its value, trading near $6,252 on Wednesday afternoon, according to CoinDesk.