Brexit: An Overnight Vote That Repriced the Pound in Hours
The pound fell over 8% against the dollar within hours as referendum results came in showing the UK had voted to leave the European Union — a result most markets had been positioned against.
- GBP/USD overnight move
- −8%+ in hours
- 31-year low reached
- Yes, briefly
- Result vs. market expectation
- Markets were positioned for "Remain"
What happened
On June 23, 2016, the UK held a referendum on whether to remain in the European Union. Polling and betting markets leading into the vote suggested "Remain" was the more likely outcome, and currency markets were broadly positioned accordingly, with the pound having strengthened in the days before the vote.
As results came in overnight and it became clear "Leave" had won, the pound collapsed against the dollar, falling more than 8% within hours to levels not seen in over three decades — one of the sharpest moves ever recorded in a G10 currency pair outside of a currency crisis.
The move happened almost entirely while major markets were closed or thinly traded, meaning many traders woke up to a price dramatically different from where they had left it the evening before, with no opportunity to react as it happened.
Why it still matters
Scheduled political events with a binary outcome — referendums, major elections, court rulings — carry gap risk that ordinary daily volatility does not. The market can be confidently positioned one way right up until the result, then reprice entirely within a single overnight session.
This is the core argument for reducing position size, or exiting entirely, ahead of a known binary event rather than holding full size through it. A stop-loss offers little protection when the price can gap straight past it — the only real control at that point is how large the position was going in.