A rare mega deal by a Chinese airline is set to revive the country’s convertible bond market, after volatile trading dried up issuance of the popular securities.

China Southern Airlines Co. on Thursday opened subscriptions for 16 billion yuan ($2.4 billion) of its convertible bonds, the largest deal for a non-financial firm since China Petroleum & Chemical Corp. sold 23 billion yuan of the notes in early 2011, according to data compiled by Bloomberg. The sale, which is also the biggest in a year and a record for the airline sector in China, comes after just eight deals were priced in September, the least since May.

Carriers around the world have struggled to stay afloat after the pandemic forced governments to shut borders and paralyzed air travel. In China, a recovery in demand for domestic flights has helped improve sentiment toward the sector, with more than 13 million passengers traveling during the key October holiday. China’s biggest three airlines probably turned profitable in the third quarter, analysts at HSBC Holdings Plc predicted.

Still, those airlines posted combined losses of almost $4 billion in the first half and the recovery won’t be enough to put them into the black by year-end.

Liquidity is a key component for professional investors looking to buy convertible bonds—the larger the deal, the more liquid the notes will be when they start trading. The sheer size of China Southern’s sale also means subscribers will get more of the bonds in their allocations. The carrier, a state-backed issuer with the highest possible credit rating, could see its notes rise as much as 18% on debut, according to analysts at Industrial Securities Co.

“I will certainly subscribe,” said Manran Ma, general manager at Beijing Mamanran Asset Management Ltd.

China Southern said in an exchange filing this week that it will use some of the proceeds to buy aircraft and aviation material, as well as to replenish capital. The firm also plans to sell as much as 10 billion yuan in short-term bonds. For the six-year convertible issue, the carrier set the conversion price at 6.24 yuan a share, according to the filing, or nearly 4% higher than Wednesday’s close. The bonds will bear interest of 0.2% to 2.0% during the term.

China’s cash-hungry banks dominate its convertible bond market after a string of mega deals in recent years. A stock rally this year encouraged smaller and lower-rated firms to tap the market, which triggered speculative trading and almost caused the first-ever default for a convertible bond in China.

Investors typically bet on convertible bonds for potential gains on the equity conversion, meaning the notes tend to rise and fall in tandem with the shares.

Chinese companies have sold a record 138 convertible bonds in 2020, already surpassing last year’s total of 126 issues. In August, notes sold by Suzhou Sushi Testing Group Co. rose 39% on their first day, while bonds sold by NanJing Sanchao Advanced Materials Co. jumped 28%. A gauge tracking the notes is up 7.3% this year.

Apart from China Southern, Xiamen Hongxin Electron-Tech Co. also opened book on Thursday for a 570 million yuan convertible bond, while two others are set to start subscriptions for similar offerings on Friday.

Demand for a slice of China Southern’s deal will likely be high, even though its shares had fallen 16% in Shanghai this year through Wednesday. In July, Sichuan Guoguang Agrochemical Co. saw its offering about 247,208 times oversubscribed.

“High-rating, large-cap convertible bonds get more attention from more institutional investors,” said Huang Lidong, investment manager at Harfor Fund Management Co. “There’s room for valuation upside for the airlines sector, thanks to gradual recovery of travel demand and earnings improvement.”