Why SentinelOne Stock Plummeted 32.4% Last Year and Has Kept Falling in 2026

SentinelOne (NYSE: S) stock suffered big sell-offs across 2025's trading. The cybersecurity company's share price declined 32.4% across the stretch, according to data from S&P Global Market Intelligence

Despite the S&P 500 index gaining 16.4% last year and the even more tech-heavy Nasdaq Composite index rising 20.4%, SentinelOne stock wasn't able to end 2025 in the green. Last year's big decline for the company's share price came on the heels of a roughly 19% decline across 2024's trading.

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Investors lost confidence in SentinelOne's growth story in 2025

SentinelOne stock saw a series of pronounced pullbacks in conjunction with earnings reports published by the company last year. While the quarterly results generally showed that revenue was continuing to grow at a robust clip, concerns about margins and forward guidance drove substantial sell-offs.

In March, the company published results for the fourth quarter of its 2025 fiscal year -- which ended Jan. 31. While sales for the period rose 29.5% year over year to reach $225.5 million and beat the average analyst estimate by roughly $3.2 million, the business's loss of $0.22 per share in the period was $0.01 worse than analysts had forecasted.

The company's next quarterly report arrived in May and triggered another big round of sell-offs. Sales and earnings for the first quarter of the current fiscal year, which ended April 30, were roughly in line with expectations -- but investors weren't happy with management's guidance.

SentinelOne stock did move higher following the release of its fiscal Q2 report, which arrived at the end of August. The company posted non-GAAP (adjusted) earnings per share of $0.04 on sales of $242.2 million, with sales being in line with Wall Street's target and earnings beating the average analyst forecast by $0.02.

Unfortunately, the company's next quarterly report didn't go over as well. Early in December, SentinelOne published results for fiscal Q3 2026 -- which ended Oct. 31. Adjusted net income of $0.07 beat the average analyst estimate by $0.02 per share, and sales of $258.9 million beat Wall Street's target by roughly $2.7 million -- but investors were looking for stronger forward guidance. News that chief financial officer Barbara Larson was retiring from her post likely also factored into the sell-off.

SentinelOne's stock slide has continued in 2026

SentinelOne's share price has continued to lose ground this year. Even though the S&P 500 is up 1.4% in 2026 and the Nasdaq Composite is up 1.2%, the cybersecurity specialist's share price is down roughly 7.3% year to date as of this writing.

SenitnelOne is now valued at approximately 72.5 times this year's expected earnings and 7.7 times expected sales. The cybersecurity industry continues to look poised for strong expansion over the long term, but investors have become less willing to back SentinelOne in light of decelerating sales growth and competitive pressures.

Keith Noonan has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends SentinelOne. The Motley Fool has a disclosure policy.