Boeing Co said on Tuesday Miami-based 777 Partners had agreed to purchase 30 more 737 MAX jets that would nearly double the private-equity firm's order book for the aircraft.

The order, valued at $3.7 billion at list prices, comes as a potential boost for the planemaker, which said last month that it had delivered 212 737 MAX jets this year, while its larger 787 aircraft remains sidelined due to production problems.

Boeing had agreed in March to sell 24 737 MAX to 777 Partners, including an option to purchase 60 more jets.

A bulk of the new order is for Boeing's 737-8-200 variant, 777 Partners managing partner Josh Wander said in a statement.

Boeing shares rose 1.5% following the announcement.