Chip maker Intel has cut its revenue forecast for the fourth quarter by about 7%, saying that floods in Thailand that have constrained hard drive production will affect PC sales.
The warning spooked Wall Street, where Intel's stock fell by almost 4% in early trading.
Intel said that it now expects revenue for the quarter to be between $13.4bn (£8.6bn) and $14bn, rather than its previously forecast range of $14.2bn to $15.2bn.
It also warned that profit margins will be slightly lower, at about 64.5% rather than 65%.
Intel is the world's biggest supplier of microprocessors used in personal computers, and has seen consistent profits as sales have grown steadily since 1985.
Intel said that it expected PC sales to rise compared with the third quarter – a growth which typically happens seasonally – but that revenues will be lower than expected because companies are reducing inventories and microprocessor purchases because of hard drive shortages.
The floods in Thailand, which killed hundreds of people, also disrupted hard drive production by companies with factories there including Seagate, Toshiba and Western Digital. World production is expected to fall by about 30% in the fourth quarter, with many of the factories and facilities underwater.
Thailand is the world's second largest source of the parts, which store data on spinning magnetic platters, unlike tablets and smartphones, which use solid-state storage and have not been affected.
Research firm iSuppli said earlier it expects global PC shipments to total 84.2m in the first three months of 2012, down from a previous estimate of 88m. That compares with about 84m sold in the first quarter of 2011, according to the research company Gartner. Intel also said it expects hard drive supply shortages to continue into the first quarter.
Generally, PC sales growth worldwide has begun to slow as the US and European economies have slowed, and as fewer companies and owners have reasons to upgrade their existing PCs. The rise of tablets such as Apple's iPad has also slowed PC sales in the west, according to analysts.
Intel's shares fell $1.12, or 4.5%, to $23.89 in morning trading on Monday, more than the general market, which was down by about 2%.