The value of bitcoins has been heavily impacted by a large scale hack of one of the currency's main exchanges: Bitfinex in Hong Kong. In reaction to the news the value of bitcoin has plummeted. Before the hack a bitcoin was worth about US$600+, as news and fear spread it bottomed out at $518 at 10pm last night. At the time of writing 1 BTC is worth approx $538.
Headlining figures concerning the hack are as folows; 119,756 bitcoins were reportedly stolen, which were worth around US$77 million at the time of purloinment. The price of BTC nose-diving shortly after this theft hit the news wires is probably the reaction of some currency holders, selling off BTC for other currencies or investments awaiting for the situation to become clearer.
Bitfinex is currently still offline. The website home page contains a statement concerning the breach of Bitfinex by hackers. It basically says that Bitfinex is aware of a breach and theft and is investigating via various channels. Furthermore, law enforcement authorities have been contacted. A Bitfinex status page will update as and when relevant information comes to light.
BitGo, the platform provider to Bitfinex is obviously under scrutiny following this hack. However this Palo Alto-based firm Tweeted that it could find "no evidence of a breach on any BitGo servers". That might suggest an 'inside job' at Bitfinex. The plot thickens as automatic restrictions concerning BTC withdrawals were bypassed. Those restrictions were put in place to limit the impact of these kinds of hacks/thefts but were obviously ineffectual this time around.
It is possible that the hack/theft could force Bitfinex into bankruptcy. Sites such as TechCrunch advise BTC holders to usually store their own coins in an offline wallet for safety.