Small oil producer RusPetro, operating fields in western Siberia, has posted a spectacular increase in its value in the past few weeks.
A recent London rally in its shares made its January share offering one of the best in the history of Russian assets, an analyst said Sunday.
The company's market capitalization broke through the $1 billion mark Friday, after the share-float pricing initially valued it at $700 million.
The surge apparently came on the heels of expectations of its inclusion into an important stock index, FTSE 250, which did indeed occur.
The announcement of the inclusion came Wednesday, and the decision will take effect March 19, the London Stock Exchange said. Entering the index, a company attracts a larger number of institutional investors, such as funds, which boosts trading in its stock.
The FTSE index includes London-listed companies primarily on account of their market value, and most of the funds will buy the new stock "automatically."
But Ildar Davletshin, an analyst at Renaissance Capital, said the company has an alluring quality that few other newcomers could match.
"It would take them a large base of reserves," he said. "It's not that simple to take hold of them."
RusPetro boasts at least one well-connected backer: the investment fund whose managing partner, Kirill Androsov, is a former deputy chief of staff of Prime Minister Vladimir Putin.
RusPetro's Krasnoleninsk field is one of the largest fields in the country, while its location in Russia's oil heartland gives the company low-cost access to pipelines, power supply and other services.