Top CEOs and financial analysts from Wall Street, including those from Goldman Sachs and Morgan Stanley, are expressing increasing concern over high market valuations and the potential for a significant correction in U.S. stocks. Multiple warnings have highlighted that the market may see a pullback of over 10%, with some predicting declines as steep as 20%. Key indicators suggest that the ongoing bull market could be in jeopardy, prompting investors to watch for signs of a market shift. Recent data points to a contraction in manufacturing activity, further fueling worries about an impending correction as optimism in the market shows signs of waning.