For many people, the TDK logo still evokes cassette tapes. That association is real. But in the year ended March 2026, Energy Application Products—including rechargeable batteries—accounted for 54.7% of TDK's ¥2.505 trillion in sales. At the same time, TDK still uses the phrase 'Evolve the Ferrite Tree' in its current management plan. The flagship products have changed, but the pattern of moving materials and process capabilities into new applications continues.
54.7%Energy Application Products share of group sales
~90%Overseas sales ratio
This is not investment advice or a stock recommendation. We reorder company-published primary-source facts to make the shape of the business easier to see.
For many people, TDK still brings cassette tapes to mind.
That memory is not wrong.
But the company looks very different when viewed through its current numbers.
First, sales are ¥2.505 trillion
The largest business is no longer tape—or even magnetic heads.
Energy Application Products account for 54.7% of sales
DATA VIEW
Energy Application Products alone account for more than half of sales
Year ended March 2026. Sales mix disclosed by TDK.
Sales mix
Energy Application Products54.7%All other sales45.3%
That can make TDK look like a battery company. But that is still only part of the picture.
Passive Components, Sensors and Magnetic Applications each remain substantial
Much of that business is invisible to consumers because the products sit inside other devices.
Roughly 90% of sales are overseas
What connects businesses that now look so different?
TDK’s own materials draw the change unusually clearly.
The business-portfolio chart starts in 1935
Cassette tapes became the product that made the name visible to a much wider audience.
From cassettes into multilayer components and batteries
That does not mean one technology moved in a single straight line.
Magnetic tapes, heads, batteries and sensors became new branches
DATA VIEW
From a cassette brand to multiple electronic-component businesses
The business and technology expansion shown in TDK's own materials.
1935Establishment
CassetteRecording media
MultilayerElectronic components
Li-ionRechargeable batteries
TDK still uses one phrase to describe the continuing branches.
It still says: “Evolve the Ferrite Tree”
The pattern of an older capability finding a new use is still visible today.
Magnetic heads now support data-center storage
Even the thin-film process behind HDD heads is being moved into another product.
HDD thin-film processes are being reused for AI data-center inductors
Seen this way, “once cassette tapes, now batteries” is too simple.
The flagship products have changed repeatedly.
But TDK keeps moving materials and manufacturing processes into new applications and adds new branches through acquisitions when needed.
THE VIEW AFTER THE NUMBERS
What the numbers suggest
Connecting the numbers makes TDK look less like a company that transformed from cassette tapes into batteries and more like a company that repeatedly moves materials and process technologies into the electronic products that matter next.
Sales reached ¥2.505 trillion in the year ended March 2026. Energy Application Products represented 54.7%, while Passive Components, Sensors and Magnetic Applications remain substantial and roughly 90% of sales are overseas.
TDK’s own materials show applications spreading from cassettes into multilayer components and batteries, while the business portfolio broadened into magnetic heads and sensors. The company still talks about “Evolving the Ferrite Tree,” and today it is moving thin-film HDD-head process technology into inductors for AI data centers. What ties TDK together is not one product. It is the habit of finding the next place for its technology.
HOYA did not simply move from eyeglasses into semiconductors. Starting from optical glass in 1941, it branched into eyeglasses, contacts, semiconductor substrates, intraocular lenses and HDD glass. Life Care still represents 62% of revenue, while Information Technology contributes 38%. HOYA plans roughly ¥92 billion of Phase 1 investment in new EUV mask blank and HDD substrate plants. The company emphasizes market structure over market size: demanding customers, close technical alignment and relationships that are difficult to switch. HOYA looks less like an eyeglass company than a company that keeps placing glass and optical technology in high-barrier niches.