The Moscow City Court has denied bail to U.S. investor Michael Calvey and ruled to extend the house arrest of Calvey and his partner, French citizen Philippe Delpal, until January 13.
The court on Tuesday upheld a previous October 9 ruling by the Basman District Court.
Calvey and several other executives and employees of the Russia-based private-equity group Baring Vostok were detained in Moscow in February and charged with financial fraud.
They all deny any wrongdoing and say the case is being used against them in a corporate dispute over the control of a Russian bank. Calvey was released into house arrest in April and had hoped to win more freedom in court.
The arrests stunned many Western investors and drew complaints from high-level Russian business leaders and government officials, who questioned the motivations of the courts and prosecutors.
Baring Vostok is one of the largest and oldest private-equity firms operating in Russia since the early 1990s, managing more than $3.7 billion in assets. The company was an early major investor in Yandex, Russia's dominant Internet search engine.
Calvey is one of two Americans currently facing potential trial in Russia on charges supporters say are groundless. Paul Whelan, a former U.S. Marine, has been behind bars since December 28, when he was arrested on an espionage charge he denies.