JAPANESE investment trusts are to step up their purchases of electronics company stocks, according to the Nihon Keizai newspaper. As of late November, electronics stocks made up 13 per cent of the investment trust companies' combined portfolios, up 0.2 percentage points from October, the paper said. The trust managers believed electronics makers' earnings would improve because the yen was now weakening against the dollar, the paper said. Faster growth in the United States economy would also benefit electronics makers, it said. The trusts were buying shares in Hirose Electric Co, Rohm Co, Mitsumi Electric Co, Matsushita-Kotobuki Electronics Industries and Sony Corp, it said. Japanese electronics makers have seen profits shrink because of the yen's appreciation against the dollar this year, and sluggish domestic sales amid a prolonged recession.