HONG KONG — Qatar Airways is buying nearly 10 per cent of Hong Kong carrier Cathay Pacific Airways for about $662 million, the companies said Monday, in a deal making it Cathay’s third-biggest shareholder.

The Middle Eastern carrier said it bought almost 3.8 million Cathay shares, which represents a 9.6% stake in Hong Kong’s biggest airline.

Hong Kong conglomerate Swire Pacific owns 45% of Cathay, state-owned Air China has 30% and the rest is publicly traded.

Qatar Airways bought the shares from Hong Kong’s Kingboard Holdings, according to a stock exchange filing by the company, which makes circuit boards and invests in property.

Kingboard expects to reap an 800 million Hong Kong dollar ($102 million) profit from selling its Cathay stake, the company said in the filing.

Cathay, which last year reported its first annual loss in nearly a decade, is carrying out a three-year corporate overhaul that includes laying off hundreds of workers as it battles to keep up with intensifying competition from rival Asian carriers.

The investment adds to Qatar Airways’ overseas portfolio. The company also owns 20% of International Airlines Group, which controls European carriers Aer Lingus, Iberia and Vueling; 10% of Chile’s Latam Airlines Group; and 49% of Meridiana, Italy’s second-biggest carrier.

Cathay shares fell 1.5% on Monday, while the benchmark Hang Seng Index finish nearly unchanged.