The owners of TUI AG are discussing a deal to combine the German travel and tourism group with its majority-owned UK business TUI Travel in a bid to cut costs, three sources close to the companies and their shareholders said.

“The idea is to bring two companies that operate in same industry together. It is a story of synergies,” a source close to one of the shareholders said. “It is being discussed right now that TUI Travel buys TUI AG,” he added.

TUI AG owns 56.4 percent of TUI Travel, Europe’s largest tour operator formed after the merger of TUI AG’s travel business and British peer First Choice in 2007.

Another of the sources said it was not feasible for TUI AG to buy the 43.6 percent of TUI Travel it does not own because it lacks the funds and has little prospect of raising money on equity markets, given it trades at a hefty discount to peers.

“There is no way to get the maths to work (for that),” that source said, adding a “reverse takeover” for around 10 euros for each TUI AG share would create value for all shareholders.

At 1225 GMT, TUI AG shares were up 5.4 percent at 7.80 euros, compared with as much as 18 euros back in 2008. TUI Travel’s shares were down 0.4 percent at 280.2 pence.

TUI AG, TUI Travel Plc and TUI AG’s main shareholders all declined to comment.

While TUI Travel comprises the whole tour operating business of the travel group, TUI AG also has hotels and luxury cruise operations as well as a stake in container shipper Hapag-Lloyd .

Ever since TUI AG in 2008 shifted its focus away from shipping and decided to sell a majority stake in Hapag-Lloyd, its shareholders have been considering ideas of how to combine TUI AG and TUI Travel to reduce overhead costs and increase combined use of resources, such as hotels.