HNA Group Co Ltd, the owner of China's Hainan Airlines, is interested in buying air cargo handler Swissport International Ltd, a source familiar with the matter told Reuters. European private equity firm PAI Partners, which owns Swissport, is looking to launch a sale or initial public offering of the company as soon as this year with a valuation of about 3.5 billion euros ($3.8 billion), Reuters reported in May. The source said HNA was one of parties interested, confirming a Bloomberg News report, but said it was one of a range of options. "The IPO option is very popular still, lots of banks are looking at it. There are lots of parties, both financial and trade, who are keen to preempt the process," the source said. Bloomberg reported negotiations could still fall apart, as the two parties have struggled to agree on price. Swissport says on its website that it provides ground services for around 229 million passengers and 4.1 million tonnes of cargo a year on behalf of some 700 aviation clients, generating operating revenue of 3 billion Swiss francs ($3.1 billion).