Dec 22 (Reuters) - Sistema says:
* Sistema subsidiary, Sistema Finance S.A., sold 6,248,227 American Depositary Shares of MTS (Mobile TeleSystems) , representing 0.63 percent of MTS's share capital, to a non-affiliated buyer for a consideration of $55.359 million net of commission.
* Following this transaction, Sistema Group's effective share in the share capital of MTS, including shares owned by Sistema through its subsidiaries, declined to 50.03 percent from around 50.66 percent.
* Sistema plans to remain the company's controlling owner.
* Mikhail Shamolin, President and Chief Executive Officer of Sistema, said: "The transaction ... generates additional resources for Sistema and allows us to continue investing in new promising projects in the Russian market." Source text for Eikon: Further company coverage: (Reporting by Moscow Newsroom)