(Reuters) – U.S. low-cost carriers Spirit Airlines and Frontier Group Holdings announced a merger agreement on Monday in a deal that values Spirit at a fully diluted equity value of $2.9 billion.

The transaction value of the deal is $6.6 billion when accounting for the assumption of net debt and operating lease liabilities, the companies said in a statement.

(Reporting by Aishwarya Nair in Bengaluru; editing by Uttaresh.V)