Germany's energy company Innogy held off supporting a 4.9 billion euro ($5.9 billion) bid by German rival E.ON, saying it was not clear if a far-reaching asset swap with its parent RWE was fair for workers or minority shareholders.

Although Innogy’s consent is not needed for the deal to proceed, its approval would smooth the process of completing the ambitious plan, which is expected in the second half of 2019. RWE said it would proceed with the transaction as planned.

Under a complex swap, E.ON will take over RWE’s stake in Innogy and keep the unit’s networks and retail activities. In addition, RWE will get a 16.67 percent stake in E.ON, minority stakes held by E.ON in two nuclear plants, Innogy’s gas storage business and a stake Innogy holds in Austrian energy supplier Kelag. 

E.ON and RWE, which holds a 76.8 percent stake in Innogy, revealed plans to break up the networks and renewables business and divide its assets in March.