Brexit: Leave the European Union, page-14

That cause no-one thought it would happen (it was a huge shock to the market and some investors sold heavily accordingly), the one who was leading the brexit wasn't confident at all before the poll (hence in the end it was only 48.2% to 51.8% unlike RAP accuracy of 90%+ and even 100%), and the caused a "shock" to the market world-wide, IMO, market has over-reacted but the market is a herd mentality and no doubt margin call and stop losses were hit contributing to the huge drops.

I expect a big bounce back on Monday.....with a lot of volatility afterwards but it won't be such a big fall like last Friday.