Morrison & Foerster (MoFo) and Skadden Arps Slate Meagher & Flom have secured lead advisory roles as Japanese telecoms group Softbank acquires a 70% stake in US mobile operator Sprint Nexel for $20.1bn (£12.5bn).

The deal, thought to be the largest ever overseas acquisition by a Japanese company, will make Softbank the world’s third-largest mobile phone operator by revenues.