Investing.com - The stock market's rally back from its February correction is showing signs of "exhaustion." That's the message from Morgan Stanley (NYSE:MS) in a note to investors. The firm says recent declines are just the beginning of what will be the biggest market correction since the one in early February.Morgan Stanley sees three reasons for concern.One is that investors don't have any good news events to look forward to in the wake of Amazon (NASDAQ:AMZN)'s blockbuster earnings and the strong GDP report. Another is a "false sense of security" among investors because disappointing earnings reports from Facebook (NASDAQ:FB) and Netflix (NASDAQ:NFLX) did not trigger a broad market selloff. Finally, Morgan Stanley says the two sectors that have led the market's gains -- tech and consumer discretionary -- are due to suffer the "rolling bear market" that has already hit the other major sectors this year.