Wall Street extended its big rally today, propelling the Dow Jones industrials up 122 points despite the absence of economic or earnings news to guide investors.

Wall Street revelled in stunning gains again today as the Dow Jones industrials surged more than 250 points, giving the blue chips their first three-day, triple-digit winning streak in 17 months.

Wall Street’s fortunes turned negative again today as a downgrade of chip makers by Merrill Lynch and retailers’ disappointing sales gave investors more reasons to doubt the strength of a business recovery. Stocks fell sharply, with the tech sector suffering the heaviest losses.