June 28 (Bloomberg) -- OAO Gazprom Neft, the oil arm of Russia’s largest company, acquired a 50 percent stake in Bennfield Ltd., the biggest shareholder of Sibir Energy Plc.

The Moscow-based company on June 22 bought Orton Oil Company Ltd., which owns 50 percent of Bennfield, Gazrpom Neft said in an e-mailed statement late Friday. Bennfield, which is controlled by Igor Kesaev and Chalva Tchigirinski, holds a 47 percent Sibir stake.

Gaining control of London-listed Sibir, which is 18 percent owned by Moscow city government, will help Gazprom Neft battle falling output from its aging fields. Sibir has rights to half of the 160,000 barrels a day produced by Salym Petroleum Development it jointly runs in Siberia with Royal Dutch Shell Plc.

Gazprom Neft is not currently in talks with other Sibir shareholders on acquiring their stakes, Chief Executive Officer Alexander Dyukov said in the statement. If a decision on buying more Sibir shares is made “we will conduct talks and, perhaps, reach an agreement on an acquisition,” he said.

Gazprom Neft has bought up 34 percent of Sibir from minority shareholders since making an offer for the company on April 23. Sibir Energy and Gazprom Neft are equal partners in a venture that controls the Moscow Oil Refinery.

The company moved to take operational control over Sibir earlier this month by appointing two of its representatives to the four-member board. Sibir shares have been suspended from trading since February following an investigation into the diversion of company funds.

To contact the reporter on this story: Denis Maternovsky in Moscow at dmaternovsky@bloomberg.net

Last Updated: June 28, 2009 07:08 EDT