Thomas Cook Group’s shares plunged by more than 25% after the tour operator issued a profit warning.
The company blamed the summer heatwave for a reduction in annual profit from a previously forecast £323 million to £280 million for the year ending on September 30.
The trading update sent Cook’s shares falling by up to 25.9% from 78p to as low as 58p in early trading on the London Stock Exchange.
Cook had been due to release its pre-close trading update on Tuesday but brought the announcement forward by one day in line with stock market rules.
Chief executive Peter Fankhauser said a “prolonged period of hot weather across Europe” had discouraged consumers from booking holidays in June and July leading to “higher than usual” levels of discounting in August.