The strategist said that there is too much negativity in equity markets.
U.S. stocks are on course for their best month this year, braving the war in Ukraine and the prospect of rate hikes.
The signal was triggered by poor investor sentiment and a surge in fund outflows.
Morgan Stanley strategist Michael Wilson called it "a vicious bear market rally."
Assets are now “more vulnerable if progress toward a resolution proves fleeting," the firm said.
A flurry of headwinds is raising fears that a downturn in equities will continue.
Banking stocks were the biggest decliners in Europe on Monday, sinking to the lowest in two months.
Hedge funds continue to rotate from growth into value, according to a recent analysis of 13F filings.
Guidance from company management has been turning more pessimistic.
Flows into equity funds that exclude the U.S. have been outpacing those for U.S.-inclusive funds.