United Heavy Machinery or Uralmash-Izhora Group, (, OMZ) is a large Russia-based international heavy industry and manufacturing conglomerate. OMZ manufactures a wide range of steel, custom and industrial components for nuclear power plants, petrochemical and mining operations and utilities. In particular OMZ is a manufacturer of reactor pressure vessels for the VVER type of nuclear reactors and the manufacturer of EKG open-cut mining power shovels.
As a Russian open joint-stock company, shares in OMZ may be publicly traded subject to terms of constitutive documents and merger agreements.
OMZ was formed in 1996 in the incorporation of Ural Machine-Building Plants with ZSMK. Izhora Plants merged with OMZ in 1999 and the company was renamed OMZ (Uralmash-Izhora Group). In 2003 the company combined with Pilsen Steel and Škoda JS, the former steel and nuclear subsidiaries of Škoda Works. In 2008 CHETENG Engineering also joined. OMZ is a 50% owner of the Uralmash Machine-Building Corporation formed in a 2007 agreement with Metalloinvest.
The company's shares were delisted from the Moscow and London stock exchanges in 2014 "due to the economic inexpedience of supporting the insignificant free-float of less than 0.33% of the capital."