The move is effectively a bet against the success of the travel giant.

Asset management firm TT International has amassed a position worth approximately £8.8 million or around 0.65% of Cook’s value.

The company joins Silver Point Capital, which has a short worth just over £10.8 million or around 0.8% of the company. A total of 1.45% of Thomas Cook’s shares are now out on loan.

Short selling is effectively a bet that a particular company’s share price will fall. Investors such as hedge funds borrow the shares on the assumption that they will go down in value. The aim is to buy them back at some point in the future at a lower price and pocket the difference.

Thomas Cook’s share price currently stands at 91p, having been as high as £1.62 almost a year ago.

The 175-year old company, which almost collapsed in 2011, has had to deal with numerous geopolitical problems in some of its key destinations, such as Turkey and Tunisia.

It did, however, bounce back into profit last year.

The company will unveil its first-half performance on May 19.

In a pre-close trading update in March, the company said that market conditions remained challenging.

At the time, chief executive Peter Fankhauser, said: “Thomas Cook continues to operate in a volatile market environment.

“We know that customers want a summer holiday but we can see that some are leaving it later to book this year as they consider their options.”

Thomas Cook declined to comment and TT International did not respond to requests.

While Thomas Cook is continuing to improve, its shares are still down on the highs of Harriet Green’s tenure. What could the short sellers have seen to pique their interest?