A spate of disappointments in the pharmaceutical and biotech sectors triggered a broad sell-off on Wall Street today, sending the Dow Jones industrials, Nasdaq composite and Standard & Poor’s 500 indexes to their lowest closes of the year.

Buying in technology stocks lifted the market today as investors bet that the beleaguered sector’s prospects for recovery were improving.

Stocks soared today while Wall Street cheered lower interest rates and a federal appeals court’s reversal of the breakup of Microsoft.