Ratings agency Moody’s Investors Service has downgraded Finland’s Fortum after it acquired a 47.12% stake in E.On spinoff Uniper for €3.8 billion.

The agency said the deal would increase Fortum’s financial leverage, and although Fortum would be Uniper’s largest shareholder, it would not be in control of Uniper’s strategy. It was not clear how much synergy there would be under the deal nor when the benefits would accrue.