FARNBOROUGH, England, July 23 (Reuters) - Qatar Airways

has ordered 20 more Boeing 777-9 planes, expanding its

order book for the U.S. planemaker's 777X family of jets to

almost 100, the companies said at the Farnborough Airshow on

Tuesday.

The order was finalised this year and was listed on Boeing's ( BA )

orders and deliveries website as from an unidentified customer.

The deal is worth around $4 billion, according to estimated

delivery prices from Cirium Ascend.

Qatar Airways said earlier on Tuesday it would decide on a

"sizeable" new order of wide-body jets around the end of this

year or in the first quarter of 2025.