OAO Magnitogorsk Iron & Steel Works has increased its stake in the charter capital of OAO Magnitogorsk Cement-Refractory Works in Chelyabinsk region from 72.93 per cent to 93.954 per cent, MMK said in an official statement late-December. According to the report, the share of common stock owned by MMK increased from 81.69 per cent to 96.255 per cent.