Bitcoin dropped 5 percent, to its lowest level since February following reports of price manipulation Wednesday.

The digital currency fell to a low of $6,133.31 as of 1 p.m. ET, according to data from CoinDesk. Bitcoin has lost half of its value this year after skyrocketing to almost $20,000 in December.

Prices began stumbling after a study was released by the University of Texas saying at least half of bitcoin’s rise last year was due to price manipulation on popular exchange Bitfinex. The 66-page paper said another cryptocurrency called tether was used to buy bitcoin at key moments when it was declining, which helped “stabilize and manipulate” the cryptocurrency’s price.

Bitcoin has fallen more than 18 percent in the past week, struggling to regain footing after dropping below $6,700 Sunday.

News of a hack at a relatively small South Korean exchange seemed to have triggered some of the weekend losses but some traders said selling was also exacerbated by investors hitting “stop losses,” and selling their bitcoins when they reached a certain price.

This break below $6,450 confirms bitcoin’s downtrend, according to one Fundstrat analyst.

“The declines over the past few days has done significant technical damage to most crypto currency charts,” Robert Sluymer, managing director and technical analyst at Fundstrat Global Advisors said in a note to clients Wednesday. “Breaking below the April lows confirms a longer-term downtrend for BTC by establishing the first lower since the uptrend began in 2015.”

The next support level is near $5,500, Sluymer said. If the current correction, which he said is a “big IF,” matched the 2014 bear market, bitcoin could see an additional 50 percent drop to the next support level of $3,200.

Despite precipitous declines in 2018, the cryptocurrency has still tripled in value since last summer.

“Bitcoin’s decline this year appears to be gathering steam, but it’s important to note that the spot price is still up over 140% from this date 12 months ago,” said Joe DiPasquale, CEO of BitBull Capital. “When compared against the meteoric 1400% increase seen overall in 2017, the gain isn’t quite as dramatic but still outperforming many other asset classes.”

DiPasquale’s research indicates a bottom around $5,000 is possible before any recovery for bitcoin.

Other cryptocurrencies fell alongside bitcoin Wednesday. Ethereum, XRP, and litecoin all dropped 7 percent, while bitcoin cash was down 5 percent.