The court rejected an appeal by lawyers acting for Vasily Aleksanyan who is accused of embezzling $460 million from Yukos production unit Tomskneft and funds from other oil companies, and of laundering another $460.8 million through his personal account in a Swiss bank.
In the appeal, Aleksanyan and his defense team said the prosecutors had failed to provide any specific evidence.
"It is an outrageous, unfair decision, which must be overturned, the criminal case closed, and Aleksanyan freed from custody," the appeal said.
Prosecutor Valery Lakhtin said there was reason to quash the ruling of the lower Simonovsky Court, which was why the Moscow City Court backed the prosecutors' position.
The Simonovsky Court ruled earlier that Aleksanyan, arrested on April 7, had committed a crime and that a criminal investigation could be launched against him.
Aleksanyan had asked Moscow City Court to grant him bail.
"I think that my custody is an unfounded, tough measure for me and my four-year-old child, whom I bring up on my own," he said. But the court ruled to remand him in custody.
Aleksanyan was detained in Moscow April 6. Moscow's Basmanny district court ordered the arrest of Aleksanyan April 7 following a request from the Prosecutor General's Office. If found guilty, Aleksanyan faces 10-15 years in jail.
Aleksanyan, who acted for ex-Yukos CEO Mikhail Khodorkovsky and former Yukos-Moscow president Vasily Shakhnovsky at their trials, said the decision to arrest him could be linked to his appointment as Yukos executive president, a move the Yukos board endorsed on April 4.
The board said Aleksanyan would be entrusted with representing the interests of stakeholders, including creditors and shareholders, and ensuring that the company's assets were protected.
Earlier, prosecutors said Aleksanyan's associates included Leonid Nevzlin, a Yukos core shareholder now living in Israel, and Dmitry Gololobov, head of Yukos-Moscow legal department. Both have fled Russia and are on an international wanted list.
The prosecutor also said a floppy disk had been found in Gololobov's office. The disk contained instructions about how to behave during an arrest, how to influence witnesses and an investigation, attract the interest of the press and escape liability.
