Seagate and Toshiba are locked in a bidding war for TDK's hard drive head business — a fight Bloomberg reports could knock Toshiba out of the hard disk market entirely and leave just two HDD manufacturers worldwide.

Seagate Technology and Western Digital already control 90% of the hard disk market, according to market researcher TrendForce. Toshiba picks up the remainder. That thin slice is now at risk over a single component.

Why one component decides Toshiba's fate

Seagate and Western Digital both manufacture their own magnetic drive heads in-house. Toshiba does not. It depends on a third party, TDK, for this critical component — and TDK also supplies Seagate and WD when they need extra capacity.

Toshiba made a bid for TDK's drive head business earlier this year to guarantee supplies, Bloomberg reported. Seagate then countered, concerned that losing access to the unit could affect its ability to meet growing demand for hard disks from AI data centers. TDK has declined to comment.

If Seagate captures the TDK unit, it could shut Toshiba out of the hard disk market altogether, according to Bloomberg. For storage buyers, that scenario means less vendor competition in a market where near-term demand from AI infrastructure buildouts keeps climbing.

How far behind is Toshiba technologically?

The supply dependency compounds a wider gap. While Toshiba relies on its suppliers for technological advances, WD and Seagate continue to push drive performance forward on their own roadmaps.

Western Digital announced two throughput-boosting technologies in February:

• High bandwidth drive technology (HBDT) — enables simultaneous reading and writing from multiple heads on multiple tracks.
• Dual pivot technology (DPT) — a second mechanical mechanism aimed at faster actuator movement.

Western Digital said HBDT alone will deliver up to twice the bandwidth of conventional HDDs.

Seagate moved on capacity. In July it launched a hard disk packing 30TB into a 3.5-inch enclosure using its Heat-Assisted Magnetic Recording (HAMR) technology. The company also announced plans to release 32TB and 36TB models next.

What should enterprise storage buyers watch?

The outcome of the TDK auction carries direct procurement consequences. If Seagate wins, Toshiba's exit would concentrate 100% of HDD supply in two vendors — at exactly the moment AI data center operators are scaling up capacity purchases. Even if Toshiba retains a supply arrangement, its dependence on a rival-owned component supplier would leave it structurally weaker.

No deal has been announced. TDK is staying silent, and neither Seagate nor Toshiba has publicly confirmed the bids. But the logic of the fight is clear: whoever controls drive head production controls who gets to build hard disks at all — and at what price — as AI-driven storage demand accelerates.