Intel Corp’s Japan unit tried to stifle competition in microprocessors by offering unfair rebates to personal computer makers, the country’s antitrust watchdog said on Tuesday in a warning against the chip giant.The warning was the Japanese Fair Trade Commission’s second such action against a computer industry giant following a similar move against Microsoft Corp last July. Intel, the world’s biggest microchip maker, immediately disputed the warning, which came with no monetary penalty. After the FTC announcement, the European Commission said it was investigating Intel for possible antitrust violations in cooperation with Japanese authorities.Japan’s watchdog said the unit stifled competition by offering rebates to five Japanese PC makers that agreed either not to buy or to limit their purchases of chips made by Intel’s rivals Advanced Micro Devices and Transmeta.The FTC said such practices had been going on since May 2002 after the inflow into Japan of low-priced personal computers heated up competition in the domestic market.That had prompted Japanese PC makers to turn increasingly to AMD and Transmeta chips, which were typically offered at a discount to Intel products, it said.The share of Intel’s central processing units in the Japanese PC market rose to 87 per cent in 2004 from 73.2 per cent in 2002, while AMD’s share halved to 10.4 per cent over the same period, according to data from research firm Gartner. “In this case, a company with a dominant market position squeezed out rivals by doing business with the five major PC makers on condition of not using competitors’ chips,” an FTC official told reporters.The five PC makers are NEC Corp, Toshiba Corp, Hitachi Ltd, Sony Corp and Fujitsu Ltd, he said.Intel said its business practices were fair and lawful and expressed concerns the FTC’s finding was not based on antitrust principles commonly accepted worldwide.