[5] Co-founders Mikhail Fridman and Petr Aven stepped down from the company in early March 2022, after the EU imposed sanctions on them in the wake of the Russian invasion of Ukraine.

[8] On 2 March 2015, Lord Browne was named executive chairman of L1 Energy, renouncing his other roles to focus on the newly formed oil and gas company.

[9] On 4 March 2015, the Secretary of State for Energy and Climate Change, Ed Davey, gave company co-founder Mikhail Fridman a one-week deadline to convince the UK government not to force him to sell the newly acquired North Sea oil and gas assets.

[10] A senior western oil executive said the UK was entering "uncharted territory" by intervening publicly in a corporate transaction over fears of the effect of future sanctions against Russia.

[13] On 14 October 2015 LetterOne Group announced that it had agreed a deal to acquire German utility Eon’s interests in three producing Norwegian fields, located in the North Sea.

[19] After receiving regulatory approval in nine countries, LetterOne merged its oil and gas businesses into Wintershall Dea, a new European exploration and production company, in May 2019.

[24] As of 2023, the firm had four main business units: L1 Health, L1 Technology, L1 Retail, and L1 Energy,[3] the latter of which is an oil and gas investment company[25] formed by LetterOne in 2015.

[9] All four units are supported by L1 Treasury Services, which manages the group's liquidity and financial investments, including private equity holdings.

[29][30] Early that month, LetterOne froze the shareholdings of two EU sanctioned directors and co-founders, Mikhail Fridman and Petr Aven, and removed them from its board, leaving chairman Mervyn Davies in control of the firm.