Bombardier has identified China's CDB Leasing as a previously undisclosed potential buyer for 15 CSeries aircraft.
The conditional purchase agreement signed on 8 July 2012 also includes options for CDB Leasing to buy another 15 CSeries aircraft.
If CDB confirms the order, Bombardier would deliver five 110-seat-class CS100 and 10 135-seat-class CS300 aircraft.
The timing for the deliveries was not disclosed.
All orders and options under the purchase agreement are valued at $2.07 billion.
Bombardier has targeted China as a likely buyer for the CSeries, and signed on aircraft manufacturer Shenyang to build the fuselage.
"It not only represents the first Chinese customer to select the CSeries airliners, but also demonstrates the flexibility designed into these game-changing aircraft," says Mike Arcamone, president of Bombardier Commercial Aircraft.