Bill Ackman, the billionaire hedge fund manager and founder of Pershing Square Capital Management, said he has taken a “large notional short position” against the Hong Kong dollar, arguing it is “only a matter of time” before the currency’s peg to the US dollar breaks.In a Twitter post on Wednesday evening in the US, Ackman revealed that Pershing Square had a “large notional short position against the Hong Kong dollar through the ownership of put options”, which would pay off if the currency’s US dollar exchange rate crashes through the floor of its narrow trading band.

“The peg no longer makes sense for Hong Kong and it is only a matter of time before it breaks,” he added.

The high-profile bet against the Hong Kong dollar puts Ackman in the company of prominent western fund managers — including George Soros and Kyle Bass — who have challenged the peg, which has operated successfully without interruption since it was first introduced four decades ago.