By Samrhitha A and Aditya Soni (Reuters) -Western Digital said on Monday it would spin off its flash memory business that has been grappling with a supply glut after talks of merging the unit with Japan's Kioxia stalled. The split will leave the data storage products maker with its traditional hard-disk drive business and create two publicly traded firms, giving into demands from activist investor Elliott. Western Digital shares rose 10% on the news. Elliott said in a statement it supports the split. The move clears years of uncertainty over Western Digital's flash memory unit that was built through its $19 billion purchase of SanDisk in 2016 and caters to the smartphone and computer industries. Demand for flash chips has slumped after the pandemic, leaving the market awash in supply and increasing the pressure on chipmakers to consolidate.