Shares of OAO Mosenergo, Russia's largest thermal power generating company, were suspended on the Russian Trading System after the stock rose as much as 13 percent.
Buying and selling of the stock was halted at 3:45 p.m. Moscow time and resumed an hour later, said Oksana Zaitseva, a spokesman for the RTS. The exchange suspends trading when a stock rises more than 10 percent in a day.
Mosenergo shares closed at 25.5 cents on the RTS, a gain of 10 percent for the trading session. In earlier trade the stock advanced as much as 13 percent.
On the Micex Stock Exchange, Mosenergo shares rose 7.8 percent to close at 6.708 rubles, after gaining as much as 11 percent earlier.
Trading in the stock was also suspended Feb. 9 on both exchanges. The shares climbed 36 percent to 7.21 rubles on the Micex that day.
``It's hard to say who is buying, but given that Gazprom has some big plans for Mosenergo, it could go a lot higher,'' said Kirill Surikov, director of international equity sales at Alfa Bank, in an e-mail message.
OAO Gazprom, the world's biggest producer of natural gas, plans to swap a stake in its petrochemical unit OAO Sibur Holding for 13 percent of Mosenergo, Vedomosti reported today, citing unnamed managers at Gazprom.
Gazprom owns 20 percent of Mosenergo directly and another 13 percent via its banking unit ZAO Gazprombank and pension fund Gazfund. Gazprom's board will discuss the swap at the end of February, the newspaper said.
Gazprombank Deputy Chief Executive Officer Alexander Sobol said yesterday that the bank owns about 10 percent of Mosenergo shares. He added that the bank is a portfolio investor rather than a strategic investor.
``Owning a stake in Mosenergo is not our strategic goal,'' Sobol told reporters. A spokesman for Gazprombank today declined to comment further on Mosenergo.
To contact the reporter on this story: William Mauldin in Moscow at email@example.com