Atum

Atum manufactures miniaturized, high-efficiency, high-output transformers and components based on core planar transformer technology, providing integrated solutions, and listed on KOSDAQ in 2023.

Its subsidiaries include a Vietnam manufacturing base, Cheonghan Electronics, which distributes MLCC and other electronic components, and DST, which precision-machines shipbuilding and industrial machinery parts.

The company's business structure spans three areas: transformer manufacturing, Cheonghan's component distribution, and DST's marine/machinery parts processing, with component distribution and marine/machinery parts currently accounting for a relatively larger share of revenue.

Atum holds an exclusive supply position for portable charger transformers in the 15W-45W range, and since 2021 has also entered the TV market, primarily supplying TV transformers to a major Korean electronics maker.

In the EV segment, the company has completed development of OBC/LDC transformers and EV charger transformers, is in technical verification with a domestic conglomerate, and has secured a six-year long-term supply contract for common-mode (CM) filters used in the integrated charging control unit (ICCU) of Hyundai Mobis's next-generation EV platform.

In North America, it is collaborating with EV commercial truck maker Harbinger Motors and LS Automotive to advance slim ICCU technology for large commercial trucks and the Tesla Cybertruck.

In the data-center segment, Atum has partnered with Seongho Electronics to jointly develop power supply units (SMPS/CRPS) for AI data centers and optical communications, aiming to expand beyond single-component transformer supply into high-output power modules.

Subsidiary Cheonghan Electronics is expanding from distribution of passive components such as MLCC, EMI shielding parts, and resistors into distribution of memory semiconductors for AI servers.

In 2025, consolidated revenue reached KRW 70.43bn, sharply up from KRW 20.44bn in 2024, but the operating loss widened to KRW 6.54bn from KRW 2.61bn the prior year, and the net loss attributable to owners grew to KRW 8.47bn.

This reflects the addition of marine and industrial machinery parts sales following the DST equity acquisition and higher component distribution revenue at Cheonghan Electronics, though the operating loss widening also appears to reflect one-off costs and business-expansion expenses recorded alongside the growth.

Revenue swung notably over the past three years, falling from KRW 38.5bn in 2023 to KRW 20.4bn in 2024 before surging back to KRW 70.4bn in 2025.

Looking at the trailing four quarters, revenue jumped from KRW 8.33bn in 2025Q2 to KRW 25.48bn in Q3 and KRW 27.68bn in Q4, then continued at KRW 26.11bn in 2026Q1 and KRW 32.30bn in Q2, roughly tripling the quarterly scale seen before subsidiary consolidation.

The operating loss narrowed from KRW 2.24bn in 2025Q2 to KRW 1.11bn in Q3 and KRW 0.96bn in Q4, widened again to KRW 1.39bn in 2026Q1, then narrowed to KRW 0.99bn in Q2.

Net income, however, followed a different pattern: in 2025Q4 the company posted a positive owners' net income of KRW 1.36bn despite an ongoing operating loss, suggesting a one-off item, while in 2026Q1 the net loss widened to KRW 3.01bn.

Over the trailing four quarters (2025Q3-2026Q2), the cumulative net loss attributable to owners totaled roughly KRW 5.88bn, indicating that despite quarter-to-quarter swings, a sustained turn to profitability has not yet been achieved.

On the balance sheet, total equity rose to KRW 14.13bn at end-2025, but equity attributable to owners fell sharply to KRW 2.79bn from KRW 11.00bn in 2024, while non-controlling interests grew to KRW 11.34bn, marking a significant shift in capital structure.

The debt ratio climbed from 166.1% in 2023 and 221.5% in 2024 to 415.8% in 2025, showing that financial leverage rose alongside the revenue expansion.

The end markets are shifting in weight from traditional mobile-charger transformers toward EV electrical components and AI data-center power infrastructure.

Global data centers are rapidly evolving toward 800-volt DC-based high-voltage architectures and megawatt-class high-power racks, increasing the importance of SMPS units that can reliably control power in confined spaces.

In the EV market, once a component is adopted into a vehicle's supply chain it is difficult to replace for an extended period, making early entry itself a source of competitive advantage.

On the competitive front, industry observers note that while conventional wound transformers made by winding copper wire face limits in automated production, yield, and heat management, Atum has demonstrated the ability to mass-produce planar transformers with a height reduced to within about 3 centimeters using a flat copper-foil structure.

In the MLCC segment, the spread of generative AI is raising server power consumption and power density, increasing demand for high-capacity, high-spec MLCCs used in GPUs and high-performance server power supplies, with large component makers such as Samsung Electro-Mechanics also expanding related long-term supply contracts.

Amid these industry trends, distributors such as Cheonghan Electronics are leveraging their existing customer networks to expand supply of components for AI servers and data centers.

The company has stated it is targeting KC certification for its 3.3kW power module within the current year and for its 12kW module in the first half of the following year, with plans to begin development of a 50kW module thereafter, ultimately aiming at the larger optical-communication and bidirectional high-output SMPS market.

Industry estimates project that subsidiary Cheonghan Electronics' memory-semiconductor distribution revenue will grow from KRW 8bn in 2026 to KRW 13bn in 2027 and KRW 18bn in 2028, raising its share of total revenue from about 25% in 2026 to roughly 34% by 2028.

In the automotive electronics segment, the company is expanding its push into the North American electric commercial-truck market through a long-term CM filter supply contract for Hyundai Mobis's ICCU and collaborations with LS Automotive and Harbinger Motors.

In December 2025, the company decided on a rights offering with public subscription of forfeited shares, issuing 4 million new common shares, with proceeds earmarked for KRW 5.34bn in facility investment and KRW 5.9bn in debt repayment.

This appears aimed at simultaneously funding new data-center and automotive-electronics investments while improving the balance sheet.

Industry observers suggest that if expanded orders in automotive electronics and AI data centers combine with growth in Cheonghan's MLCC and memory-semiconductor sales, the scope for earnings improvement could widen, though this remains a forward-looking expectation rather than a confirmed outcome.