PARIS (Reuters) - China Aircraft Leasing Group Holdings (CALC) 1848.HK is among the inaugural customers for a larger new version of Boeing's 737 jetliner, two industry sources said on Saturday.

A model aircraft is displayed at the reception of the China Aircraft Leasing Group office in Hong Kong, China June 22, 2015. REUTERS/Bobby Yip

The Boeing 737 MAX 10 will be launched at the Paris Airshow on Monday with the backing of at least two Chinese lessors - CALC and the aviation arm of China Development Bank, whose interest in the aircraft emerged earlier this week.

Boeing and CALC declined to comment.

CALC’s purchase of the newest variant of Boeing’s most-sold jet is seen as part of an order for 50 aircraft from the 737 MAX family announced by the Hong Kong leasing firm this week.

CALC, part-owned by China Everbright Bank 601818.SS, reported the overall order on Thursday but did not disclose a breakdown by type of model.

It is the company’s first Boeing order and will diversify its portfolio following previous Airbus purchases.

The stock exchange posting on the eve of the world’s largest air show is the most concrete sign so far that the widely expected launch of the Boeing 737 MAX 10 is going ahead, subject to the formal approval of Boeing directors.

The launch is expected to trigger a procession of roughly 150 mostly small- to medium-sized orders from airlines, industry sources said.

These include low-cost operators Lion Air of Indonesia and India’s Spicejet.

Ireland's Ryanair RYA.I has confirmed it is looking at the jet, but is not expected to strike a deal in time for the show.

Expectations were diminishing as the show approached of an order for the jet from United Airlines UAL.N, which Boeing had been actively wooing as a marquee customer.

The 190-230-seat Boeing 737 MAX 10 is designed to plug a gap at the top end of Boeing’s single-aisle range after strong sales of the competing Airbus A321neo.

It will be delivered from 2020.

Boeing and Airbus are preparing to squeeze the last drop out of a recent flood of airplane orders without the razzmatazz of recent years at the show starting on Monday.

As often happens when markets soften, leasing companies will be looking for bargains in Paris next week and are expected to feature prominently in any announcements beyond the MAX 10.

A handful of airlines were said to be shopping for planes in advance of the show including Peruvian low-cost startup Viva Air, owned by Irelandia Aviation led by the son of Ryanair founder Tony Ryan, which could place an order for Airbus.

Saudia budget subsidiary Flyadeal, which has already leased Airbus jets, could soon opt to buy some, industry sources said.

Airbus declined comment. Neither airline could be reached.