STMicroelectronics will quit ST-Ericsson by the third quarter of 2013.
This announcement boosted the share price of the French-Italian chip maker to the top of benchmark indexes in Paris and Milan.
ST-Ericsson specialises in mobile-phone microprocessors. The joint venture is equally owned by STMicro and Swedish group Ericsson. Since it was created in 2009, it was never profitable.