Tour operator Thomas Cook has formed a strategic partnership with LMEY Investments to grow its own-brand hotel portfolio, as it confirmed its full-year outlook. 

As part of the deal, Thomas Cook acquired a 42% stake in Aldiana, a German tour operator and hotel management firm, from the Swiss-based hotel development company. 

Thomas Cook's chief executive Peter Fankhauser said the acquisition was a significant step in the firm's strategy to expand its range of own-brand hotels. 

"The development of a strong portfolio of own-brand hotels is absolutely key to our success," Fankhauser said in a statement. 

"Our new strategic partnership with LMEY, with its proven track record of identifying and redeveloping highly successful properties in sun and beach locations, gives us the perfect launch pad to accelerate this critical part of our strategy," he added. 

Thomas Cook operates or franchises over 180 hotels in 17 countries, with 11 new hotels added this summer.

Rival TUI is also investing more into its own hotel portfolio, including setting up its own brand TUI Blue. 

The partnership follows an alliance with Expedia to make the online travel company its preferred provider of hotels for holiday sales that are not in Thomas Cook's own-brand offering. 

Thomas Cook said that summer trading was ending as expected and its full-year earnings outlook was unchanged. 

The company said its summer season was 91% sold, which is 2% more than the same time last year, and that sales to Spain remained level with last year despite a highly competitive market.

Thomas Cook also said its German airline Condor, with bookings up 12%, was benefitting from the uncertainty surrounding the fate of Air Berlin, which filed for insolvency in August. 

Condor was among those interested in bidding for Air Berlin assets to shore up its position in Germany, but Air Berlin's creditors have instead opted to hold talks with Lufthansa and EasyJet.