Joseph Tsai, Executive Vice Chairman of Alibaba Group, attends the Alibaba Group's 11.11 Singles' Day global shopping festival in Shanghai, China, November 11, 2017. REUTERS/Aly Song

(Reuters) - Alibaba Group Holding Ltd co-founder Joseph Tsai is nearing a deal to buy the 51% stake he does not already own in the U.S. basketball team Brooklyn Nets, a source familiar with the matter told Reuters.

The deal would value the NBA team at $2.35 billion, the source said.

If the negotiations conclude successfully, a deal could be announced as early as this month, the source said.

Russian billionaire Mikhail Prokhorov had sold a 49% stake in the team to Tsai in April last year.

Tsai had then reserved the option to acquire additional shares in 2021, which would make him the controlling owner.

The sale would mark a new record for a U.S. professional sports franchise, the Wall Street Journal reported first on Wednesday. (on.wsj.com/2yWmOsx)

The Brooklyn Nets declined to comment on the deal.