Wall Street slid on Friday in a broad sell-off, rounding out a topsy-turvy week in which investors juggled signs of economic strength with concerns over corporate tax increases, stress from the Delta COVID variant, and possible shifts in the U.S. Federal Reserve’s timeline for tapering asset purchases.

All three major U.S. stock indexes fell, with the Nasdaq Composite Index suffering the biggest decline as rising U.S. Treasury yields pressured market-leading growth stocks. They were also on track to post weekly losses, with the S&P index setting a course for its biggest two-week drop since February.

“We’re seeing a market where investors are pulling to the sidelines,” said Peter Cardillo, chief market economist at Spartan Capital Securities in New York. “It’s a market that’s being driven by cautiousness rather than any shift in fundamentals.”

A potential hike in corporate taxes could eat into earnings also weigh on markets, with leading Democrats seeking to raise the top tax rate on corporations to 26.5% from the current 21%. While consumer sentiment steadied this month it remains depressed, according to a University of Michigan report, as Americans postpone purchases while inflation remains high.

Inflation is likely to be a major issue next week, when the Federal Open Markets Committee holds its two-day monetary policy meeting. Market participants will be watching closely for changes in nuance which could signal a shift in the Fed’s tapering timeline.