FILE PHOTO: The flag of Uniper SE flutters in front of the utility's firm headquarters previously used by German utility giant E.ON in Duesseldorf, Germany, June 8, 2016. REUTERS/Wolfgang Rattay/File Photo

FRANKFURT (Reuters) - Hedge Fund firm Knight Vinke has increased its holding in Germany's Uniper UN01.DE to 5.02 percent, adding it would not tender that stake to Finland's Fortum FORTUM.HE as part of a 8.05 billion euro ($9.5 billion) takeover offer.

Knight Vinke’s increased investment comes a day after Elliott Management said it had raised its holding in Uniper to 7.38 percent. Elliott has not said how it will respond to the takeover offer.

Knight Vinke, which has been a shareholder since September 2016, said it was not acting in concert with any other shareholder.

A source close to the firm said Knight Vinke was not under any legal obligation to state that it was acting on its own, but did so for clarification to the market.

“They’ve got their agenda, Elliott have their own agenda,” the person said.

A spokeswoman for Elliott declined to comment.

The news comes ahead of plans by E.ON EONGn.DE, Uniper's former parent, to tender its remaining 46.65 percent stake in Uniper to Fortum for a fixed price of 22 euros per share by Jan. 11, 2018, which is below its current share price.

The offer extends to all Uniper shareholders under German takeover rules and runs until Jan. 16.

Uniper shares were down 1 percent at 26.065 euros by 1157 GMT.