Semiconductor stocks are falling again after a weak earnings report from Intel Corp. (INTC.O), the world’s second-biggest chipmaker, brought Thursday’s relief rally to a screeching halt.

Rivals Advanced Micro Devices Inc. (AMD.O) and Nvidia Corp. (NVDA.O) each fell more than two percent in extended trading after Intel’s revenue forecast for the first quarter fell short of the lowest analyst estimate tracked by Bloomberg. Intel fell as much as 8 per cent.

Intel’s report came just minutes after the Philadelphia Semiconductor Index closed with its biggest gain in nearly a month. Thursday’s 5.7 per cent rally was sparked by optimism after better-than-expected results from Texas Instruments Inc., Xilinx Inc. and Lam Research Corp.

Also contributing to the gloom late on Thursday was Western Digital Corp., a maker of hard drives and memory chips. Shares of the company sank 5 percent after second-quarter earnings and net revenue fell short of estimates. Micron, the biggest U.S. memory maker, fell 2 per cent. An exchange-traded fund that tracks the Philadelphia Semiconductor Index sank 1.6 percent post-market.