LONDON (Reuters) - The steadying of Russia's economy does not yet merit a stabilization of its sovereign rating outlook, credit rating agency Moody's said on Tuesday.

"We have a negative outlook which reflects Russia's ongoing challenges, including - despite a recent recovery - an environment of subdued commodity prices relative to pre-crisis," Moody's top European sovereign analyst Dietmar Hornung told the Reuters Global Markets Forum.

"(There is) no improvement to the extent that we would consider stabilization of the outlook at this juncture."

Moody's retains a negative outlook on its 'junk' grade Ba1 rating on Russia, but an oil price rise back to $50 a barrel and a tight grip on its finances has helped the country's economy this year.

"If we had signs of significant improvement on the medium-term economic outlook and an improvement with respect to the investment climate in Russia and a replenishment of the fiscal buffers, all these factors would be credit positive," Hornung added.

(Reporting by Marc Jones; editing by Kirsten Donovan)