Seagate Technology Stock Slides 15% Over 5 Straight Down Days
A five-day slide in Seagate Technology (STX) stock has erased about $30 billion from its market value. The company’s valuation now stands at about $174 billion after the shares fell a cumulative 15% over the streak.
For anyone holding the stock, the price is now about $771.81 a share as of 9/15/2026.
How The Streak Stacks Up Against The S&P 500
Here is how STX stock stacks up against the S&P 500 over the streak and the periods around it:
| Return Period | STX | S&P 500 |
|---|---|---|
| 1D | -4.2% | -0.4% |
| 5D (Current Streak) | -14.7% | -1.1% |
| 1M (21D) | -20.7% | -2.6% |
| 3M (63D) | -24.2% | 0.4% |
| YTD 2026 | 180.9% | 10.8% |
| 2025 | 225.3% | 16.4% |
| 2024 | 4.1% | 23.3% |
| 2023 | 69.1% | 24.2% |
What does the business look like at this new price?
The recent decline is specific to the stock, not the broader market. During the five-day slide, the S&P 500 returned -1.1%. The sources for this note do not show why the move happened. While the streak is notable, it is not unique; 30 other S&P 500 stocks are currently on losing streaks of 5 days or more.
The underlying business fundamentals present a mixed picture. Revenue over the last twelve months grew 34.1% and its operating margin is 34.7%, both above the medians for S&P 500 Information Technology stocks. However, the stock trades at a price-to-earnings multiple of 54.5, which is also above the sector median of 36.1.
A streak is information, not an instruction.
A string of losses or gains tells you that a stock has the market’s attention and that momentum is a factor. It is not a signal to buy or sell. The disciplined response is to use the new price as a reason to re-evaluate your own view of the company’s value.
The numbers here provide a starting point for that work: weighing the company’s growth and margin profile against its current valuation.
A slide like this poses an obvious follow-up: which marked-down stocks are actually worth buying? Our Buy the Dip screen runs that test every day, flagging beaten-down names whose fundamentals still hold up.
A Slide Like This Is Why Diversification Exists
Watching one stock fall day after day is the clearest lesson the market teaches about single-name risk. Whether this particular decline is an opportunity or a warning, the deeper point is the same: no one name should be able to do this to your portfolio.
The Trefis High Quality (HQ) Portfolio is built on that principle: roughly 30 businesses selected for consistent cash generation, strong margins, and resilient balance sheets, sized and rebalanced with rules. It has a track record of outpacing a benchmark that combines the three major indices – the S&P 500, S&P Mid-cap, and Russell 2000. Study the slide; spread the risk.