Russia’s second-largest mobile phone operator is closing in on a merger to create the world’s fifth-largest mobile carrier by number of subscribers.

The Associated Press reports that Amsterdam-based VimpelCom will merge its phone assets with Weather Investments, a privately held telecommunications investment company owned by Egyptian billionaire and telecom mogul Naguib Sawiris. The companies turned to two longtime outside legal advisers from Am Law 100 firms to negotiate the deal.