Vinson & Elkins has advised China Petrochemical Corporation (Sinopec) on its purchase of a 10 percent stake in Sibur, Russia’s top petrochemical company, for $1.338 billion.

The deal was signed in September in Beijing during Russian President Vladimir Putin’s visit, and was finalised in December.

Sinopec will also acquire an additional 10 percent stake in Sibur within the next three years, Reuters reported.

The Vinson & Elkins team was led by partners Xiao Yong in Hong Kong, Jay Kolb in Beijing, Natalya Morozova in Moscow and Rob Patterson in Abu Dhabi.

“Sinopec’s 10% minority investment in Sibur not only deepens the cooperation between the two companies, but also represents an active implementation of China’s One Belt, One Road policy,” said Wang Yupu, chairman of Sinopec, in a joint press release issued by Sibur and the Chinese company.

“Sibur’s vertically-integrated upstream and petrochemicals business model is highly complementary with Sinopec’s businesses. This transaction is in line with our objective to strategically expand our petrochemical business overseas. Our continued partnership will help diversify and secure Sinopec's long-term sourcing of petrochemical products.”