HELSINKI (Reuters) - Finnish utility Fortum (>> Fortum Oyj) has been offered just 0.22 percent of shares in Germany's Uniper (>> Uniper SE) by Tuesday on top of a 46.65 percent stake that it bought from E.ON (>> E.ON), a regulatory filing showed.

Fortum on Monday reported a larger combined stake of 47.04 percent, but now said it had to revise that figure due to a booking mistake at a shareholder custodian bank.

Fortum in September clinched a deal to buy E.ON's stake, and then launched a full takeover bid worth 8.05 billion euros (7.15 billion pounds) to all Uniper shareholders due to German takeover rules.

Uniper has considered the bid as hostile and too low.

The offer ends on Tuesday but an additional acceptance period is expected to take place between Jan. 20 and Feb. 2.

(Reporting by Jussi Rosendahl, editing by Terje Solsvik)

Stocks treated in this article : Fortum Oyj, E.ON, Uniper SE