It's been a tough week for Plus500.

The trading company, which lets people place bets on stock and currency markets through something called a contract for difference, has had 578 million ($896 million) wiped off it's value in just the last week after a hellish 66% share price fall in five days.

Plus500 was valued by the market at around 862 million ($1.33 billion) last Friday. By the time markets closed in London yesterday it was worth 284 million ($440 million). 

The company's share price collapse began on Monday when word began to emerge that some customers' trading accounts had been frozen.

Plus500 eventually admitted that just over half of accounts in the UK had been frozen while it carried out beefed up checks to make sure its customers weren't money laundering. Shares fell 37% on the day.

Stock continued to fall on Tuesday before flat-lining for most of Wednesday and Thursday. 

Then on Friday it nosedived again after a fund shorting the company posted an online blog alleging there were more deep-rooted problems at the business and setting a price-target of just 76 pence ($1.18) when shares were trading around 275 pence ($4.26).

Plus500 suspended shares pending an announcement, which people assumed would be about the blog post.

But it turned out to be more information about the account freezes, as Plus500 revealed they came up after a review of security ordered by Britain's financial watchdog.

That didn't do much to help things and when Plus500 resumed trading the share price kept falling, ending the day down 35%.

The company may not have even hit the bottom yet. CEO Gal Haber told investors to expect an update at next Wednesday's annual general meeting. Depending on what exactly is in that update we could see shares fall even lower.

NOW WATCH: Here's what 'Game of Thrones' stars look like in real life

See Also:

Plus500 just told us that the UK's financial watchdog is behind its account freezes This analyst thinks Plus500's account freeze could cost it 25 millionUPDATE: London-listed spreadbetting firm Plus500's stock bombs after freezing accounts