Sony Corp. said Thursday it will halve the number of parts suppliers to slash costs under a turnaround plan that is testing the mettle of Chief Executive Howard Stringer.

The electronics and entertainment giant plans to cut purchasing costs by ¥500 billion, or 20 percent of the ¥2.5 trillion spent in the business year ended in March, company spokeswoman Mami Imada said.

Sony has been restructuring under Stringer, a Welsh-born American who in 2005 became the first foreigner to head Sony.