Bitcoin has continued its 4-day downward trend, declining 17% from $7,600 to a current $6,300. The currency is now approaching its 2018 low of $6,000 that was achieved on February 5, though it's still up 220% from its $2,725 value one year ago. The bear market is also hitting other cryptocurrencies, with total crypto market cap declining from over $300 billion to $270 billion now.
The reason behind the decline is not clear. Today (Wed) researchers published a study alleging price manipulation using Bitfinex's Tether stablecoin, claiming that US Dollar equivalent Tether was used to support prices during sell periods and to further push prices up during buy periods. Tether is currently the #11 cryptocurrency in market cap, with $2.5 billion on the market.
The manipulation allegations, while severe, were only published today so are unlikely to be the key factor in declining crypto prices.