Inside every hard drive, a tiny part floats just above a spinning disk. It reads and writes your data. It is called a head, and only one company in the world makes them to sell to anyone who asks: Japan’s TDK. That is why the Seagate TDK bidding war, first reported by Bloomberg on October 6, matters far more than its price tag.
Three drive makers, one outside supplier
The hard-drive business has shrunk to three companies: Western Digital, Seagate and Toshiba. There used to be more. Samsung, for example, sold its drive business to Seagate in 2011 for about $1.4 billion.
The three do not stand on equal ground when it comes to heads. Seagate and Western Digital mostly make their own. Toshiba makes none. It buys every head it uses from TDK.
That one fact turns a quiet parts business into a strategic prize.
What was reported
According to Bloomberg, Toshiba started talks with TDK about buying the heads business in the spring. Seagate then came in over the summer with a higher offer. The deal could be worth several billion dollars.
Toshiba pushed back, sort of. A spokesperson said the report was inconsistent with the understanding of the company and its main owner, Japan Industrial Partners, and did not explain further.
Why would TDK sell? The heads business earns thin returns, about 4% on the money invested in it, according to TrendForce. TDK would rather put that money into batteries, sensors and other parts with fatter margins.
Why anyone wants it now: AI
For years, hard drives looked like a fading technology. Solid-state drives (SSDs) were faster and smaller.
AI changed that. Data centers need somewhere to keep huge piles of training data and results. Hard drives store the same amount of data for far less money than SSDs. So the old technology is suddenly in short supply, and drive makers have raised prices.
That is also why Toshiba wants to grow. On October 2, Nikkei reported that Toshiba plans to double its AI data-center drive capacity within fiscal 2027, investing about 60 billion yen (around $380 million) in its plant in the Philippines. Toshiba holds roughly 10% of the market today and is aiming for 30%. Seagate fell 12% that day.
But there is a problem in that plan. More drives need more heads. And Toshiba gets all of its heads from TDK.
Who wins, who pays
Picture the two outcomes.
If Toshiba buys TDK, it locks in its own supply for the expansion. It would also own a part its two rivals sometimes buy.
If Seagate buys TDK, Toshiba’s growth plan suddenly depends on buying parts from its direct competitor. That is a little like opening a bakery when the only flour mill in town belongs to the bakery across the street.
Seagate faces a hurdle, though. Wedbush analyst Matt Bryson noted that Seagate would likely run into antitrust problems. Regulators tend to look hard at deals that let a big player control a rival’s supply.
(I wrote earlier about why Samsung chose to buy a key chip part instead of building it. The Seagate TDK fight is the same question from the other side: what happens when the part you buy is owned by the company you compete with.)
How the market took it
Investors did not like the uncertainty. On October 6, Seagate fell about 8.9% to roughly $808, and Western Digital dropped about 6.4%. Seagate was down about 14% from the previous Thursday.
Even so, both stocks are still far above where they started the year, thanks to AI demand. Seagate reports earnings around October 28. That call may be the first place anyone from the company is asked about TDK in public.
My take: Heads, Seagate wins. Tails, Toshiba pays.
Not advice. Just how I see it.