Coutts & Co. has moved its U.S. stock holdings to an exchange-traded fund that would benefit from a rally in the pound if the U.K. government defies the odds to secure a new trading relationship with the European Union.

The firm said it was responsible for most of the $350 million outflow from the London-listed Lyxor S&P 500 ETF over the past week that was then invested into a sterling-hedged version of the same fund.

The allocation would outperform if the currency rebounds against the dollar after falling 4.6% in September, on track for the worst monthly slide since October 2016.

“We think the pessimism over the U.K. is overdone,” said Alan Higgins, chief investment officer at Coutts with about £30 billion ($38 billion) in assets overall. “Based on game theory, we think there’s a deal to be done between the U.K. and Europe. Markets will be surprised, and that will result in higher sterling.”

Sentiment toward U.K. assets is tumbling anew. Domestic stocks are on track for a 5.2% decline this month, the worst since the March rout. The EU has stood firmly against Prime Minister Boris Johnson’s bid to rewrite parts of the withdrawal agreement, setting the stage for a chaotic exit next year.

Coutts, a unit of Natwest Group, is using the Lyxor ETF to give U.K. private clients exposure to U.S. stocks without taking currency risk. The money manager is replicating a similar strategy using derivatives in its multi-asset funds. Modest interest-rate differentials across the Atlantic also mean it’s relatively cheap to hedge against currency swings.

Even if a Brexit agreement remains unresolved, Higgins still sees merit behind the sterling-hedged S&P 500 position. A protracted period of dollar weakness and a low bar for the pound to rebound from its post-referendum quagmire would boost the ETF investing strategy.

“The bias is for the dollar to go down against all currencies,” he said. “Even if sterling is in a bad place, there’s an upward bias on sterling.”