U.S. stocks weakened Thursday in the run-up to Wall Street's main event for the week, a speech by Federal Reserve Chair Jerome Powell coming on Friday.

The S&P 500 fell 0.9% for its worst day following a two-week rally. The Dow Jones Industrial Average dropped 177 points, or 0.

4%, and the Nasdaq composite sank 1.7%. Stocks fell as Treasury yields cranked up the pressure in the bond market following some mixed data on the U.

S. economy, which has been slowing under the weight of high interest rates meant to get inflation under control . One report showed slightly more U.

S. workers applied for unemployment benefits last week than expected. The number is still low relative to history, but the uptick could signal a job market that continues to cool.

A second report, meanwhile, suggested U.S. business activity remains deeply split.

Growth for services businesses is accelerating, according to preliminary data from S&P Global Market Intelligence. But the country’s manufacturing sector appears to be contracting at a more severe rate. Overall, the data suggested the U.

S. economy is still growing but pointed to some fragility. “Growth has become increasingly dependent on the service sector as manufacturing, which often leads the economic cycle, has fallen into decline,” said Chris Williamson, chief business economist at S&P Global Market Intelligence.

The Fed has pulled its main interest rate to the highest level in more than two decades in hopes of restraining the economy enough .