Deutsche Lufthansa AG said it plans to increase its stake in charter airline Eurowings to 49% from 24.9% at the start of next month.
Lufthansa did not give any financial details of the deal with the airline that is also the owner of low-cost airline Germanwings.
Last year newspaper reports indicated that Eurowings' biggest shareholder Albrecht Knauf planned to exercise an option this spring which would force Lufthansa to buy a 24.1% stake in the charter airline.
This would see Knauf's stake fall to 51% from 75.1%, the Financial Times Deutschland reported.