Orrick Herrington & Sutcliffe, Skadden Arps Slate Meagher & Flom and Magisters have lined up on a $23.8bn (£16.4bn) deal – the largest merger in Ukrainian history.

The deal, completed on 21 April, saw Russia's Altimo and Norway's Telenor combine their stakes in cellular operators Russian Vimpelcom and Ukrainian Kyivstar GSM to create Vimpelcom.

Orrick acted for Telenor outside the Ukraine, with corporate partner Peter O'Driscoll leading the deal alongside counsel Nell Scott and Vladimir Markin, senior associate Sushila Nayak and associate Louiza Savchenko. Asters partners Oleksiy Didkovskiy and Igor Svechkar acted for Telenor in the Ukraine.

Magisters and Skadden acted for Altimo, with managing partner Andrew Mac heading up the Magisters team alongside counsel Oksana Ilchenko and senior associates Oleg Boichuk and Aleksandra Yevstafyeva. Corporate partner Kirill Ratnikov acted for the firm in Russia.

Mac said: "This transaction required tremendous efforts and co-operation over nearly a four-year period between different practices and offices. In addition, the deal is taking place amid the worldwide economic crisis and changes in Ukraine, which also left a footprint on this already complex project."

Corporate partners Lorenzo Corte and Pranav Triedi led Skadden's team alongside international securities partner Richard Muglia, international finance partner Alexey Kiyashko and associates Alexander Tarabrin and Jason Givens.

JP Morgan and ING acted as underwriters advising Telenor. Morgan Stanley and Credit Suisse were the deal managers for Altimo.

Click here for more international news, comment and analysis