The newspaper, citing sources, said dual-fuel gas and electricity prices are to increase by 8.7pc, pushing up the average bill by £109 a year.
It expects an announcement to be made on Monday.
A spokesman for E.ON said on Friday that the company would announce any energy price rises first to its customers and that it had made "no announcement" yet.
E.On is the only Bix Six supplier not to have announced an autumn or winter price rise. It has previously said that it would leave prices unchanged for the rest of the year.
EDF Energy will increase gas and electricity prices by 10.8pc from today, while British Gas, Npower, SSE and Scottish Power have already raised their prices.