China Southern Airlines Co. said it will buy 100 Comac C919 jets, bolstering the streak of recent orders for the local planemaker vying for a role alongside incumbents Boeing Co. and Airbus SE.

The Guangzhou-based carrier’s purchase is valued at US$9.9 billion at list prices, it said in an a filing Monday. 

Read More: Air China Orders Homegrown C919s in Challenge to Jet Duopoly

The deal means China’s three largest state-owned carriers have now ordered a combined 300 single-aisle jets from Commercial Aircraft Corp of China Ltd., while maintaining large a backlog with Airbus and Boeing.

China Eastern Airlines Corp Ltd. kicked off the mega-orders on Sept. 29, striking a deal with the planemaker better known as Comac for 100 single-aisle aircraft. Last week, Air China also announced a plan to buy 100 units of the jet, which is similar in size to the Airbus A320 and the Boeing 737.