Originally Fennovoima was created as a partnership between Voimaosakeyhtiö SF, a cooperative producing electricity for its owners' needs at production cost in proportion to their ownership share (Mankala), with 66% and the German power company E.ON with 34%.

[8] Although RAOS Voima was prepared to take 49% in the project, Voimaosakeyhtiö SF commits to own more than half of the power plant and aims to increase the share of Finnish companies up to 66%.

[15][16] On 28 February 2014 Voimaosakeyhtiö SF made the final decision to participate in Fennovoima's nuclear power plant construction.

[17] In August 2015 the public was informed that Migrit Solarna Energija would not be involved in the venture after it was reviewed to be owned by Sberbank Russia.

[19] The company's financial plans assume the plant will be able to sell electricity at no more than 50 €/MWh across its lifetime,[20] while the International Energy Agency estimates LCOE of 150 $/MWh for nuclear in the EU in 2020 (115 $/MWh in 2050), twice as expensive as offshore wind (75 $/MWh).