Traders preparing for a Halloween shock in currency markets after the last Brexit deadline placed bets worth billions of pounds in options, most of which expired worthless on Friday.
Sterling is holding its ground above $1.29 after the European Union gave the UK another three-month extension to the previous October 31 exit date. 
That left many options maturing Friday out of the money, including a notional value of over £10bn ($13bn) that the currency would slump below $1.28 or climb above $1.30.
“Implied volatility is quite expensive as in such an binary environment it is a preferred way to express positions,” said Andreas Koenig, head of global currencies at Amundi Asset Management, which oversees $1.7tn. “One day we will know, deal or no deal, in or out. But towards this final certainty it remains binary and the preferred management tool will be still options.”
These options, giving investors the right to buy or sell at those levels, may have been placed as hedges or as bets on a sharp move for a last-minute Brexit deal or if the UK crashed out of the bloc at midnight. Speculation in the pound has emerged as a political issue, with allegations that Prime Minister Boris Johnson has links to such investors and rival Jeremy Corbyn attacking hedge funds at the start of a campaign for a December election. In total, more than £20bn worth of options expired at 2pm in London on Friday, according to data from the Depository Trust & Clearing Corp, an unusually high number when it comes to the pound-dollar currency pair. 
Those having bought the options would only lose the premium paid, which still could be costly.
“The question of timing and maturity of the option is very important, especially because of the special situation of so many moving deadlines,” said Koenig. “I don’t think there is any no brainer solution.”
Speculators have reduced net short positions on the pound this month to the least since June. Hedge fund manager Crispin Odey, highlighted by Labour leader Corbyn, is a Brexit supporter who has shorted the pound, but has dismissed talk that Johnson’s links with investors like him amounts to a conflict of interest.
With the election set for December 12 and the next Brexit deadline of January 31, both dates are likely to draw renewed hedging in the pound. For now, traders are expecting calmer times with a gauge of two-month swings in the currency near the lowest in six weeks.
“We know we have a delay to Brexit and again we know the date, so although volatility will be high on those dates, it is being sold off outside those dates,” said Neil Jones, head of currency sales for financial institutions at Mizuho Bank Ltd. “Consequently high and low pound strikes may well expire out the money.”