An international arbitration court ordered India’s Tata Sons to pay Japan’s NTT Docomo $1.17 billion for the Japanese firm’s stake in the failed Tata Docomo joint venture.

Docomo, which acquired a 26.5 per cent stake in Tata Teleservices in 2009 for about $2.2 billion, decided to pull out of the struggling venture in 2014. It exercised an option in the original agreement that required Tata Sons to find a buyer to take its stake at 50 per cent of the original price or at the fair market value, whichever is higher. Docomo filed for arbitration in January 2015, claiming the Indian firm failed to fulfill its obligation to find a buyer.

The London court ruled that Tata Sons, the parent company of Tata Teleservices, was in breach of the shareholder agreement and ordered it to buy back the Japanese firm’s stake for $1.17 billion.

Despite Docomo’s victory, some analysts doubt the Indian firm can afford to make the payment and also question where the agreement complies with Indian regulations, which ban the sale of stakes in companies for more than their fair market value.

With pressure from the Indian government to streamline rules to encourage greater foreign investment, the central bank was considering suspending the rules that prevented Tata Sons from paying more than the current fair value of Tata Teleservices’ shares. But the Reserve Bank of India ended up rejecting that request last year.