Once one of New York City’s most valuable start-ups, Blue Apron has seen its fortunes shrink since its painful I.P.O. in June, which came just days after Amazon announced plans to acquire Whole Foods for $13.7 billion and launch its own meal-kit delivery service, sparking fears that the newly public company could be facing an existential crisis.

Now, less than a month after going public, Blue Apron is shaking up its C-suite, announcing Tuesday that co-founder Matt Wadiak will be stepping down from his role as C.O.O. to be a senior adviser at the company. Blue Apron gave no reason for the change in Wadiak’s role. Blue Apron’s V.P. of supply chain Tim Smith will also be promoted to S.V.P. of consumer products, reporting directly to C.E.O. Matt Salzberg. “As a co-founder and member of our executive leadership team, Matt Wadiak has played an instrumental role in driving forward Blue Apron’s mission to make incredible home cooking accessible to everyone,” Salzberg said in a statement. “His contributions to the company have been immeasurable and we thank Matt for his unwavering dedication over the past five years.”

The executive shake-up quickly reversed a day of gains after a number of analysts gave Blue Apron a buy rating; including Goldman Sachs, which assigned the company a buy rating and an $11 price target, above its $10 opening price; and Oppenheimer, which gave Blue Apron an outperform rating and an $11 price target. This vote of confidence from investors, including from some firms that had underwritten Blue Apron’s I.P.O., sent the company’s stock surging in pre-market trading on Monday, but were reversed on news of Wadiak’s retreat.

On Tuesday, Blue Apron’s stock price traded around $7.50, and in pre-market trading Wednesday, it hovered around $7.25, higher than its $6.49 low last week, but still far below its $10 I.P.O. price. Still, some on Wall Street suggest that the threat from Amazon could be overrated. As SunTrust analyst Youssef Squali argued in a note on Monday, Blue Apron has a first-mover advantage and brand recognition that Amazon, for all its reach, currently lacks. “There are a number of instances where the worst fears from the threat of Amazon’s potential entry into a vertical have failed to materialize,” he wrote. Investors are still waiting to be convinced.