Debevoise & Plimpton's London and Moscow offices have picked up a lead advisory mandate on the merger of Russian potash companies Uralkali and Silvinit, in a deal that will create a combined business worth $23.9bn (£15.4bn).

Debevoise has advised Uralkali on the merger, which will see Uralkali acquire 20% of Silvinit for $1.4bn (£903,300m) and complete the tie-up through a share swap.

The US firm fielded a team led by City managing partner James Scoville and Moscow-based corporate partner Alan Kartashkin. Silvinit relied on in-house counsel.

Kartashkin said: "This is probably the first statutory merger transaction in Russia between two independent public companies of this scale and magnitude, so the structuring of the transaction was particularly interesting."

He added: "It is quite unique as there are very few share for share deals in Russia. There are a lot of advantages in structuring a transaction in Russia as a statutory merger, such as the absence of a mandatory tender offer and more favourable tax treatment, and I think it is quite likely that more companies will follow suit."

The deal, which is subject to shareholder approval, will be voted on early next year. If it goes ahead the combined company will be called Uralkali and will become the world's second largest potash producer behind Canada's PotashCorp.

The merger comes after a $41.9bn (£27bn) hostile bid for PotashCorp by BHP Billiton fell through last month. That deal saw Slaughter and May, Cleary Gottlieb Steen & Hamilton and Blake Cassels & Graydon each handed a role.