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Seagate stock price falls after CEO Dave Mosley's rattling supply chain warning

By Peace Longe TheStreet

Updated May 21, 2026 10:30 AM

A throwaway line from a CEO rarely moves an entire sector in a single afternoon. Dave Mosley managed it on Monday.

Speaking at the JPMorgan Global Technology, Media and Communications Conference, as reported by Benzinga, the Seagate Technology (STX) chief was asked a simple question: would the company build new factories to chase soaring AI storage demand?

His answer rattled the room. New plants "would just take too long," he said, and could leave Seagate with more capacity than it needs.

That single comment dragged down the whole memory group, pulling Micron (MU), Western Digital (WDC), and SanDisk (SNDK) lower with it.

It leaves the stock with one debate it cannot dodge, and a high-stakes earnings report waiting just over the horizon.

Dave Mosley's warning that new factories "would just take too long" underscores Wall Street's unease over whether AI storage demand is outrunning supply.

Photo by SOPA Images on Getty Images

How far Seagate stock fell after the Mosley warning

Seagate shares closed Friday at $795.47, within striking distance of their all-time high.

Then Monday hit. The stock dropped as much as 7.5% intraday, touching a low near $723 before steadying, according to Investing.com.

It clawed back some ground by midweek, closing Wednesday at $751.07, up 2.42% on the day.

Add it up, and STX sits roughly 6% below its pre-warning level, and about 10% under the $834.01 record close it set on May 11.

More memory and AI stocks:

The selling spread fast. Western Digital and SanDisk both fell alongside Seagate, with Western Digital trading 4.5% lower and SanDisk down 2.5% at one point.

When one storage CEO says he can't build fast enough, the market reads it as a sector-wide ceiling.

What Mosley actually said about wafer lead times

Here is the part that spooked investors. Mosley explained that Seagate's recording head wafers now carry lead times ofmore than nine months, with finished drives taking another quarter on top of that, Yahoo Finance reported.

A recording head wafer is the precision component that lets a drive read and write data, and it sits at the very start of a long build cycle.

So the company runs a build-to-order model, giving it visibility only four to five quarters out.

"We want to keep that four or five quarters of visibility very, very solid," Mosley said, according to CNBC. "But the demand is significantly higher than that."

Diverting engineers to spin up new factories, he argued, would slow the pace of technology improvement that actually drives Seagate's margins.

While Mosley was simply making an honest comment, investors heard a leader admit that his company cannot scale fast enough to capture the AI buildout in front of it.

The supply-versus-demand debate Wall Street needs settled

This is the question now hanging over the stock: is Seagate's AI-storage boom supply-constrained or demand-constrained?

The distinction matters more than it sounds, because each path leads somewhere very different for the share price.

If growth is capped by how many drives Seagate can physically make, the upside has a ceiling that no amount of demand can lift.

If the constraint is genuine scarcity against runaway demand, then Seagate holds rare pricing power, and the bears are early.

Management has handed both camps ammunition. Nearline capacity, the high-capacity drives sold straight into cloud data centers, is almost fully allocated through calendar 2027, with customers already engaging on 2028 supply, Yahoo Finance notes.

That kind of forward visibility is rare for a hardware company. Whether you read it as a wall or a moat depends entirely on which thesis you already hold.

The bear case: a richly priced stock with no room to slip

Start with valuation, because that is where the skeptics live.

STX trades around 69 to 70 times trailing earnings after a run that saw the stock climb more than 600% over the past year.

That price leaves almost no margin for error. A single soft quarter, a delayed product ramp, or a hint of softening cloud capex could trigger a sharp repricing.

The memory sector also has a history here. It has been burned by overcapacity before, with brutal price wars and margin damage that took years to repair.

UBS captures the caution. According to TipRanks, the firm raised its target to $545 from $515 but kept a Neutral rating, warning the market may already price in the structural improvements.

There is also the substitution risk. If solid-state drives encroach on nearline workloads, today's pricing power could fade faster than the bulls expect.

The bull case: scarcity, pricing power, and rising targets

The other side reads the same facts and sees strength.

Citi analyst Asiya Merchant points to "sustained robust demand" and a tight supply backdrop, framing the lead-time problem as proof of how badly customers want Seagate's drives.

The fundamentals back the optimism. Fiscal Q3 2026 revenue rose 44% year over year to $3.11 billion, with record non-GAAP gross margins of 47%.

Management raised its medium-term revenue growth target to at least 20% a year, up from a previous low-to-mid-teens estimate, per Seeking Alpha.

The price targets reflect the conviction:

Where other Wall Street firms see Seagate stock heading

Rosenblatt: raised to $1,000 from $500, the boldest HDD call of the year
Evercore ISI: raised to $1,000 from $750
Bank of America: lifted to $840 from $700
Goldman Sachs: raised to $700 from $385

Sources: Yahoo Finance, 24/7 Wall St., Investing.com

For long-term holders, scarcity locked in by contract and underpinned by AI capex looks more like durable pricing power than a growth ceiling.

What still has to happen for the bull thesis to hold

A blowout quarter is already in the rearview. The next real test comes when Seagate reports fiscal fourth-quarter results, the close of its June fiscal year, expected in late July, per MarketBeat.

Management has already set a high bar. The company guided to fiscal Q4 revenue of $3.45 billion, plus or minus $100 million, and non-GAAP EPS of $5.00, plus or minus $0.20, per its SEC filing.

That midpoint implies revenue growth of about 41% year over year, so anything short of it would hand the bears their proof point.

Here is what will actually move the stock when those numbers land:

Four things Seagate needs to confirm at fiscal Q4 earnings

A clean revenue and margin beat against the $3.45 billion and $5.00 EPS guidance, not just an in-line print
HAMR and Mozaic ramp progress, including the Mozaic 5 platform targeting 50-terabyte drives by late 2027
A quantified demand gap, so investors can see exactly how far demand now exceeds supply
No cracks in pricing discipline, since management has said there are "no changes" to its pricing strategy

If management can put numbers behind "demand is significantly higher" than supply, the bull case strengthens. Vague reassurance will not be enough at this valuation.

What this means for investors right now

For anyone weighing STX, the practical takeaway is about position sizing and patience, not bravado.

The stock is volatile by nature, with 44 moves greater than 5% over the past year. A 6% slide on a CEO comment is normal turbulence for this ticker, not necessarily a thesis-breaker.

If you already own it, the fiscal Q4 report will be a cleaner read than this week's price swings. Wait for the numbers and the demand commentary before adding or trimming.

If you are looking to start a position, the valuation argues for caution. Buying a stock priced near perfection means you inherit all the downside of any stumble.

The honest framing: Seagate's lead-time problem can be bullish or bearish, and the next earnings call is where management has to tell investors which one it is.

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This story was originally published May 21, 2026 at 10:07 AM.