Vedomosti quoted Gutseriyev as saying Russneft, one of Russia's top ten oil companies producing 300,000 barrels per day, told his employees prior to his departure that he was being forced out and cited pressure from law enforcement and tax authorities.
Prosecutors charged Gutseriyev with "serious law violations committed by an organized group" after Russneft offices were raided and the company president questioned early this year.
Experts say Gutseriyev has made the right decision because otherwise he would have followed in the footsteps of Mikhail Khodorkovsky, the founder of the Yukos company, who is now serving an eight-year sentence in Siberia for fraud and tax evasion.
Vedomosti said the new owner of Russneft will be 39-year-old tycoon and Russia's second richest man, Oleg Deripaska, the owner of Basic Element (BasEl).
Gutseriyev, who bought some Yukos assets shortly before it was declared bankrupt last August, said he had been forced to quit the business.
"I received a proposal that I leave the oil business quietly but I refused," he said in an address to his staff carried by corporate newspaper Vremya Russnefti July 23. "Then the company came under unprecedented harassment to make me more willing to compromise."
Vedomosti cited a source close to Deripaska as saying the businessman had talked to Gutseriyev and agreed the deal last week. A spokesman for BasEl told the paper that several affiliated companies had filed a request with the Russian anti-monopoly authorities to approve the acquisition.
A source close to Deripaska said the deal would be worth within $6 billion, but a source close to Russneft gave the $9.6 billion figure.
A source close to the deal said Gutseriyev would only receive about $3 billion, and the buyer would pay the company's $2.8-billion debt to state-owned lender Sberbank and Swiss trader Glencore, and cover back taxes, which tax authorities put at 20 billion rubles ($780 million).
Founded in 2002, Russneft acquired about 30 production units with reserves totaling 600 million metric tons in five years using financial aid from Glencore. The company is a vertically integrated oil holding, which also includes three oil refineries, two transportation units and 300 gasoline stations.
