"The fines have been set at 1.356 billion rubles ($47 million) for Gazprom Neft and 1.112 billion rubles ($40 million) for TNK-BP," a spokesman said.
Both companies said they would appeal the fines. "We were not aware of the FAS decision, but we intend to contest it," a Gazprom Neft spokesman said.
"TNK-BP is ready to use all capabilities envisaged by law, including applying to a court to appeal the FAS decisions, including those imposing a fine," the British-Russian oil company said in a news release.
The TNK-BP Management company and Gazprom Neft, the oil producing arm of energy giant Gazprom, were found to be in breach of competition laws in September. The anti-monopoly service said two weeks ago that the fine would be at least 1 billion rubles for each company.
The regulator sent inquiries to crude producers LUKoil, Gazprom Neft, Surgutneftegaz, TNK-BP, Rosneft and other companies in July over hikes in fuel prices, and demanded in September that seven of them cut prices.
Allegations against Surgutneftegaz have been dropped.