BTC/USD has broken major support $600 and declined till $540 at the time of writing. It is currently trading at $586 (Bitstamp).

Ichimoku analysis (Daily chart):

Tenkan-Sen level: $683

Kijun-Sen level: $623

Trend reversal level - (90 day EMA)-$521

“BTC/USD has taken support near 90 day EMA and any break below confirms further weakness, a decline till $449 (200 day MA) is possible”, FxWirePro said in a statement.

Long-term trend remains bullish for the pair. It faces major resistance is around $625 (daily Kijun-Sen) and any break above will target $645 (21 day MA)/$685(7 day EMA). On the downside, short-term support is likely to be found at $521 (90 day EMA) and any violation below will drag the pair till $449 (200 day MA). Short-term trend is weak for the pair.

Speaking with CoinDesk, Arthur Hayes, co-founder and CEO of bitcoin leverage trading platform BitMEX, attributed the plunge in bitcoin price to the coming ‘Brexit’ vote.

"The drop below $600 indicates that many traders believe that 'Bremain' will prevail. The vote is still too close to call with various polls indicating 'Brexit' and 'Bremain' in a dead heat”, Hayes said.