Merlin Entertainments (LON:MERL) dropped 5% after it said the disruption caused by the crash would hit profits by up to £47m.
Profits for the theme parks division in 2015 are expected to be between £40m and £50m, compared with £87m last year
The Alton Towers theme park owner said that the recent accident in which four people were seriously injured has had an adverse effect on trading. The summer season has been slow, with several rides, including the one that malfunctioned, temporarily closed. Merlin have also suspended advertising for its theme parks, and rides at other sites were also closed temporarily.
Merlin shares fell as much as 8% in the first few minutes of trade, although they recovered to be down 3.5% at 408p by mid-morning.
Merlin’s profit report led the FTSE 100 index down 19.06 points to 6,560.75.
Shares in Pearson (LON:PSON) were also down 2% after it confirmed it was in talks to sell its 50% stake in the Economist. This came just after it announced on Friday it would be selling the Financial Times after 60 years of ownership.
However, mining shares were up, with Randgold Resources (LON:RRS) the top riser in the FTSE 100, climbing 3.1%, and mining giant BHP Billiton (NYSE:BHP) was up 2.4%.