CEOs of Wall Street heavyweights Morgan Stanley and Goldman Sachs on Tuesday cautioned that equity markets could be heading toward a drawdown, underscoring growing concerns over sky-high valuations.

The stock market marked its biggest decline in nearly a month after Wall Street shed highflying technology stocks. The S&P 500 dropped 1.2%. The Nasdaq Composite slid 2%. Both marked their biggest daily declines since Oct.

U.S. stocks bounced around their records on Wednesday after the Federal Reserve made moves to boost the job market but also warned that more help isn’t guaranteed.