Uniper, Germany's largest gas trader, late on Sunday disclosed the award, saying it had to make the payment to a European energy company without identifying it.
The arbitration proceedings, under the rules of the International Chamber of Commerce, began in early 2021 and relate to the pricing provisions of a long-term LNG supply agreement with the counterparty, Uniper said.
The LNG contract in question was concluded before Uniper's spin-off from E.ON (EONGn.DE) in 2016 and expired last year, Uniper said, adding that no further financial fallout was to be expected as a result.
Eni supplied Uniper with 0.65 million tonnes of LNG per year between 2007 and 2022, according to the 2017 annual report by the International Group of LNG Importers (GIIGNL).
Uniper declined to comment while Eni was not immediately available for comment.
Thinly-traded shares in Uniper, which became Europe's most high-profile corporate victim during last year's energy crisis, closed 1.8% higher on Monday.
Uniper last year launched legal proceedings against Russia's Gazprom (GAZP.MM), its former main supplier of natural gas, which first cut and later suspended deliveries, causing Uniper to nearly collapse.
Uniper said the award "related to the retroactive re-pricing of the long-term agreement", without being more specific. Arbitration proceedings over gas supply contracts are not uncommon in the industry.
Uniper, which was bailed out by Germany last year, said the payment would impact its annual results, adding it was currently analysing the decision and would review legal steps. It did not provide an updated fiscal outlook.
Uniper in October confirmed that it expects adjusted earnings before interest and tax of 6 billion to 7 billion euros and adjusted net profit of 4 billion to 5 billion euros in 2023 thanks to lower-than-expected gas spot prices.
