The company's stock was down by 6.1% as of 12:58 p.m. EDT.
Raymond James analyst Robert Majek said that some demand for the company's services could be flat after the first quarter, and management could issue conservative second-quarter guidance when it reports earnings next week.
Investors may have reacted so strongly to Majek's downgrade of Fastly's stock today because tech stocks have become increasingly volatile since the beginning of this year.
Many technology stocks, including Fastly, were able to benefit from lockdowns and social distancing because their services thrived as people spent more time online.
But as the U.S. economy has started to open back up and more Americans have received the coronavirus vaccine, investors have shifted their attention to other sectors of the economy.
With today's downgrade of Fastly's stock, investors have found even more reason to look beyond the tech sector for new investments.
Fastly's stock is down about 24% since the beginning of this year. Investors can likely expect some more share price swings as the company releases its first-quarter results on May 5, and as investors try to figure out which companies will benefit as the U.S. economy opens back up.