Brexit Exit Polling by Hedge Funds
The British government allows large hedge funds to conduct their own exit polling. They are not allowed to release their findings until 22:00 British Summer Time (BST) — there is no prohibition against their trading based on their own Brexit exit polling.
Properly sampled Brexit exit polling in UK voting is extremely accurate (usually within a +/- 1% error). Hedge funds will have a good indication on the Brexit vote by midday BST and will almost certainly have solid data by 18:00 BST. There is an embargo on publishing results until 22:00 BST. Thus, hedge funds will have a lead of many hours over the average market speculator.