Some media earlier reported that the bank had acquired Troika Dialog due to the investment company's liquidity problems.
"These reports of an alleged deal by Sberbank of Russia to purchase investment company Troika Dialog are not true," Sberbank's statement said.
Troika also issued statement denying the report, and saying: "Troika Dialog remains an independent company and continues to follow its earlier selected and announced strategy."
Arkady Dvorkovich, a presidential economic adviser, said the government could help Troika Dialog and other struggling Russian companies and banks to find new shareholders, if necessary.
Many Russian banks and companies are experiencing liquidity problems and have seen their value dragged down by huge losses on the Russian stock market since May.
On September 17 trading was suspended for two days after share prices plummeted to their lowest levels in nearly three years on the RTS and MICEX stock exchanges amid worsening global financial troubles.
The market rebounded on September 19 after the government took urgent measures to pump billions of dollars into it to shore up liquidity.
Dvorkovich said: "The sale of a stake in equity is the business of shareholders. Troika Dialog is one of the largest and strongest investment banks in Russia. I believe the company today has considerable potential to operate on its own on the market, receiving loans from other banks."
Earlier this week, the investment bank Renaissance Capital, a direct competitor of Troika Dialog, struck a deal with Russian billionaire Mikhail Prokhorov's investment vehicle Onexim Group on selling 50% minus one share to Prokhorov for $500 million in an apparent drive to shore up its liquidity.
