SilkAir, the regional carrier owned by Singapore Airlines, finalized an order for 54 Boeing 737s including 31 of the planned 737 MAX 8.

The deal pushes Boeing’s total orders for the MAX to 969, the company said.

At list prices, the order is worth $4.9 billion, but actual prices estimated by Avitas are about half that.

The order is the largest ever placed by SilkAir, which currently operates a fleet of 21 Airbus planes.