Arabtec said its board had approved the purchase of 149.6 million shares in Depa - valued at Dh241.6 miillion ($65.8m) based on yesterday's closing share price on Nasdaq Dubai - and it would take effect on November 22.
The builder, in which Abu Dhabi investment fund Aabar owns a stake, said it was buying the shares from various investment funds. It did not disclose the price it paid for the shares.
Shares in Depa soared yesterday, hitting a five-month high at $0.44. About 150 million shares changed hands, which is more than what the company's shares traded in the previous two years combined.
Depa said in a statement yesterday that "the name of the purchaser, the size of their current stake and their intentions are unknown."
Arabtec and a consortium of Turkish and Greek firms were awarded a $2.9 billion contract in June to build a mid-field airport terminal in Abu Dhabi. In the same month, Depa and its German joint venture partner saw a $245 million contract to fit out the new Doha International Airport terminated.
Depa has been involved in a number of high-profile projects in the United Arab Emirates, including the fitting of the interior for the Burj Khalifa, the world's tallest building.