Re-Ranking 19 Korean AI Data-Center Stocks: Power, Cooling and Backup Systems Before Operators

Thu, 23 Jul 2026 13:35:00 +0900

At 1:29 p.m. KST on July 23, GnCenergy was up 29.5%, SK Gas 11.4%, LS ELECTRIC 11.2%, LS Materials 10.9% and Seojin System 12.6%. Korea’s AI data-center power theme had returned in force.

That price order is not the same as an investment ranking. GnCenergy has the cleanest backup-power exposure, but it had already risen 77.9% over the prior 20 sessions. LS ELECTRIC has a confirmed KRW 318.96 billion contract, yet trades near 61.6x 2026 earnings while foreign investors sold KRW 198.7 billion over 20 sessions. LG Electronics, by contrast, combines chillers, coolant distribution units and direct-to-chip cooling. Its shares fell 10.7% over the same window while foreign and real-money investors bought KRW 85.5 billion and KRW 105.3 billion.

That distinction drives this report: business directness and a good entry price must be scored separately.

Related context This is the market and flow update to the July 4 AI data-center power bottleneck map. Company-specific context is available in our work on GnCenergy, VinaTech and Bloom Energy, SK Gas LNG cold energy and SK Gas versus SK Oceanplant. See also the Exclusive Analysis Hub and Korean AI Companies Hub.

TL;DR

Korea’s data-center theme mixes operators, facility and power suppliers, and AI server component vendors. The first revenue capture often sits with power, cooling and backup-power suppliers. Operators initially carry capex and only generate attractive returns after securing utilization, power economics and tenant contracts.

We score 19 names across three dimensions.

Dimension	Weight	What it measures
Fundamentals and direct exposure	40%	Confirmed contracts, product and customer directness, repeat-order potential
Foreign and real-money flow	35%	20-session foreign flow plus insurance, funds, private funds and pensions
Valuation and entry position	25%	Forward P/E, recent return, intraday spike and price response to flow

The current risk-adjusted order is LG Electronics, Iljin Electric, Samsung SDS, GST and SK Gas.

Bucket	Names	View
Begin watching or scaling	LG Electronics, GST	Lower price burden with accumulated flow
Flow-confirmation candidate	Iljin Electric	Direct orders and reasonable valuation, but foreign buying must persist
Wait for a pullback	Samsung SDS, SK Gas	Strong theses, less attractive after the July 23 move
High quality, early entry	SK Telecom, Sanil Electric, HD Hyundai Electric, Seojin System	Flow conflict, high expectations or balance-sheet questions
Do not chase	GnCenergy, LS ELECTRIC, Hyosung Heavy, VinaTech, LS Materials, Gaon Cable	Direct exposure is offset by price, valuation or weakening flow

1. Method

Item	Basis
Live price	Naver Finance at 13:29 KST on July 23, 2026
20-session return	June 24 close to July 22 close, adjusted Naver FChart prices
Investor flow	June 24 through July 22, Kiwoom REST `ka10059`, amount basis
Real money	Insurance, investment trusts, private funds and pensions; financial-investment desks excluded
Valuation	July 22 Naver/WiseReport consensus and July 23 intraday price

We recalculated returns from Naver’s adjusted-price series because the local prices_daily table contained corporate-action adjustment errors in a few names. July 23 prices are intraday, not closing prices. Forward multiples for thin-consensus and loss-making companies are only rough reference points.

2. Three Different Data-Center Trades

Operators

Samsung SDS, NHN, SK Telecom, LG Uplus, KT and NAVER own or rent data-center and GPU capacity to sell cloud, GPUaaS and enterprise AI services. Their earnings path runs from site and power procurement to construction, anchor customers, utilization and finally operating profit.

SK Telecom’s up-to-15GW plan is a useful scale marker, but remains a plan that depends on sites, power, tenants and financing.¹ NHN Cloud is one step further along, having begun service on a 7,656-B200-GPU cluster in Yangpyeong.²

Facility and power suppliers

Switchgear, transformers, cables, backup generators, ESS and cooling systems can recognize sales from the order and construction phase, before the operator reaches mature utilization. This is the most direct early-cycle listed-equity layer. The risks are one-off contracts, customer concentration, input costs and working capital.

AI server components

Samsung Electronics and SK Hynix memory, FADU enterprise SSD controllers, Isu Petasys networking PCBs and Samsung Electro-Mechanics or Daeduck substrates respond more to server configuration, accelerator units and memory content than to the number of buildings.

The key is timing. Facility suppliers capture the front end of the investment cycle. Operators capture recurring revenue and platform value later.

3. Direct Beneficiaries

Area	Company	Ticker	Directness	Evidence
Distribution systems	LS ELECTRIC	010120	A+	KRW 318.96bn of Bloom-linked North American data-center switchgear and distribution transformers
Backup generation	GnCenergy	119850	A+	Naver, KT and LG Uplus references; Paju AIDC cooperation
Special transformers	Sanil Electric	062040	A	KRW 50.3bn Bloom-related U.S. data-center transformer contract
Power buffer	VinaTech	126340	A	KRW 41.2bn Bloom-related supercapacitor system contract
High-voltage cable	Iljin Electric	103590	A-	Repeat 275kV cable orders for Malaysian data centers
MV cable and bus duct	Gaon Cable	000500	A-	U.S. AI data-center medium-voltage cable and local capacity expansion
Grid package	HD Hyundai Electric	267260	A-	North American data-center and grid transformers and distribution packages
Transmission	Hyosung Heavy Industries	298040	B+	High-voltage transformers and reactors for grid expansion
Cooling	LG Electronics	066570	A-	Chillers, CDUs and direct liquid cooling as an integrated package

LS ELECTRIC’s contract equals 6.42% of 2025 revenue and runs from April 28, 2026 to March 29, 2027.³ It is among the clearest disclosed contracts in the theme.

LG Electronics is different. Cooling is not yet large enough to drive group earnings, but it is one of the few large listed Korean vendors able to offer chillers, a 1.4MW CDU, direct-to-chip cooling and air systems together.⁴ In the LG group’s Paju AIDC design, LG Electronics provides cooling, LG Energy Solution provides power equipment and LG Uplus operates the site.⁵ The company said chiller orders tripled in 2025 and expected full-scale order and revenue recognition from 2026.⁶

4. ESS, Power Quality and Fuel

The second line includes Seojin System’s enclosures and racks, Samsung SDI and LG Energy Solution battery systems, LS Materials ultracapacitors, Samwha Capacitor power components and SK Eternix’s distributed-power and PPA optionality.

VinaTech’s move from cells to system-level delivery can raise content value, but customer concentration and production margins remain decisive. Seojin System shows a sharp flow conflict: foreigners bought KRW 128.9 billion over 20 sessions, while real-money investors sold KRW 30.5 billion and the stock fell 34.7%. Its roughly 11.5x 2027 P/E should be treated as a turnaround estimate, not as proven cheapness.

SK Gas offers an unusually broad option set across the 1.2GW Ulsan GPS plant, KET LNG terminal, LNG cold energy and SK’s AIDC buildout. The missing bridge is economic ownership: the power contract, cold-energy tariff, PPA economics and profit attributable to SK Gas are not public.

5. Operators

Company	Ticker	Core asset	What must be proven
Samsung SDS	018260	Samsung Cloud and 60MW Gumi AI data center	Customer ramp and cloud-margin conversion
NHN	181710	Gwangju/Yangpyeong AI data centers and GPUaaS	Utilization, pricing and post-depreciation returns
SK Telecom	017670	Ulsan and DSX large-scale AI Cloud	Financing, tenants, utilization and ROIC
LG Uplus	032640	Pyeongchon and Paju AIDC	Occupancy and long-term leases
KT	030200	kt cloud and IDC	Indirect listed exposure because kt cloud is private
NAVER	035420	GAK Chuncheon/Sejong and own AI Cloud	AI-service monetization, not only infrastructure

Samsung SDS has a 60MW Gumi AI data-center plan and said an anchor customer had already been secured.⁷ Its balance sheet and captive demand make it the most comfortable operator exposure, but a 22x-plus 2026 P/E needs cloud and generative-AI revenue to lift margins.

SK Telecom has excellent recent flow: foreign investors bought KRW 71.5 billion and real money KRW 80.1 billion. At around 17x 2026 earnings, however, the market is already assigning some AI-infrastructure value. The next rerating needs contracted customers and an explicit return framework, not only a 15GW ambition.

6. The Current Top Ten

This is an entry ranking, not a permanent business-quality ranking.

Rank	Company	20D return	Foreign / real money	Current valuation	July 23 intraday	View
1	LG Electronics	-10.7%	+KRW 85.5bn / +105.3bn	2026E P/E 15.0x	KRW 184,300, +0.9%	Accumulation candidate
2	Iljin Electric	-17.8%	-24.3bn / +10.7bn	2026E P/E 19.3x	KRW 64,600, +6.1%	Flow-turn candidate
3	Samsung SDS	+3.3%	+0.9bn / +57.4bn	2026E P/E 22.4x	KRW 207,000, +5.6%	Quality core
4	GST	-16.0%	+7.7bn / +4.7bn	TTM P/E about 14.4x	KRW 43,050, +1.7%	Deep-alpha candidate
5	SK Gas	+10.1%	-0.4bn / +7.4bn	2026E P/E 4.6x	KRW 254,000, +11.4%	Wait for pullback
6	SK Telecom	+3.4%	+71.5bn / +80.1bn	2026E P/E about 17.0x	KRW 99,000, +5.2%	Great flow; verify ROIC
7	LG Uplus	+4.6%	-2.2bn / +31.7bn	2026E P/E 8.7x	KRW 14,730, +0.6%	Defensive AIDC
8	Sanil Electric	-25.2%	+28.9bn / -33.3bn	2026E P/E 26.1x	KRW 177,200, +6.3%	Wait for institution turn
9	HD Hyundai Electric	-15.2%	-148.1bn / +14.5bn	2026E P/E 31.8x	KRW 857,000, +7.8%	Great company, early entry
10	Seojin System	-34.7%	+128.9bn / -30.5bn	2027E P/E about 11.5x	KRW 40,800, +12.6%	High-risk turnaround

7. Why LG Electronics Ranks First

LG Electronics has the best balance of product breadth, flow, valuation and unpriced optionality.

It can combine chillers, CDUs, direct liquid cooling and air systems. Foreign and real-money investors bought together while the share price fell 10.7% over 20 sessions. At roughly 15x 2026 earnings, it is cheaper than the large electrical-equipment leaders. The July 23 move was also limited to about 1%, reducing chase risk.

The cooling business still needs proof at group level. If global orders translate into disclosed revenue and margin, the multiple can expand. If cooling orders lag while core-business profitability weakens, the option should not be assigned a large value.

8. Iljin Electric, Samsung SDS, GST and SK Gas

Iljin Electric

Iljin combines direct data-center cable orders with a lower multiple than the large electrical-equipment leaders. Real money bought KRW 10.7 billion over 20 sessions, and foreign flow turned positive by about KRW 5.8 billion over the latest five. A further three to five sessions of foreign buying would turn the case from oversold to flow reversal.

Samsung SDS

Real money bought KRW 57.4 billion over 20 sessions and was a net buyer on 16 of those days. The share price rose only 3.3%. The 60MW Gumi project, Samsung Cloud and enterprise generative AI make it the safest operator exposure, but an entry near KRW 200,000 would be more attractive after the July 23 rise.

GST

GST is not yet a proven data-center cooling supplier. The case is a profitable semiconductor scrubber business with low leverage plus a low-cost immersion-cooling option. Foreign and real-money flow were both positive while the stock fell 16%. A commercial cooling order, not another pilot, is the catalyst.

SK Gas

SK Gas is the cheapest name in the group at about 4.6x 2026 earnings, but the July 23 11.4% rise reduced short-term margin of safety. A revisit to KRW 230,000-240,000 or a disclosed power/cold-energy contract would offer a cleaner entry.

9. High-Quality Names to Wait On

SK Telecom has the best flow but needs financing, tenant and ROIC evidence. LG Uplus is a lower-multiple defensive AIDC exposure, though the profit contribution remains small. Sanil Electric has a strong Bloom contract and high margins, but real money sold KRW 33.3 billion. HD Hyundai Electric’s order quality is excellent, but 31.8x 2026 earnings and heavy foreign selling leave limited room for error. Seojin System needs institutional flow, working-capital and cash-flow confirmation.

10. Do Not Chase Direct Exposure

GnCenergy is the cleanest backup-power beneficiary, but a 77.9% 20-session gain and a 29.5% intraday rise leave poor entry asymmetry. LS ELECTRIC’s contract is real, but so are a 61.6x 2026 P/E, KRW 198.7 billion of foreign selling and an 11.2% intraday rise. Hyosung Heavy combines strong earnings with a roughly 34x multiple and selling by both foreign and real-money accounts. VinaTech has a real Bloom contract but a trailing loss and real-money selling. LS Materials and Gaon Cable lack a comfortable combination of confirmed incremental earnings, valuation and flow.

11. Action Framework

Name	Approach	Confirmation
LG Electronics	Scale gradually	Support in the mid-KRW 180,000s, continued dual flow, cooling revenue conversion
GST	Small pilot position	KRW 41,000-43,000 support, stable core earnings, commercial cooling order
Iljin Electric	Flow-confirmation entry	Three to five more sessions of foreign buying and acceptance near KRW 64,000
Samsung SDS	Wait for pullback	Re-test near KRW 200,000 with continued real-money buying
SK Gas	Wait for price or contract	KRW 230,000-240,000 or disclosed AIDC power/cold-energy economics

The upside catalysts are additional LG Electronics cooling orders, repeat Iljin data-center cable contracts, Gumi utilization and cloud-margin evidence at Samsung SDS, a commercial immersion-cooling order at GST, and disclosed PPA or cold-energy economics at SK Gas.

The thesis fails if data-center starts and equipment orders are delayed, large contracts prove one-off, input and financing costs erase backlog margins, operators cannot achieve utilization, or cooling and ESS products remain pilots rather than commercial revenue.

Conclusion

The Korean AI data-center theme needs three separate lenses: operators, power and cooling suppliers, and server components. Suppliers capture the front of the investment cycle through orders and backlog. Operators earn the long-duration value only after filling their centers and recovering power and depreciation.

LS ELECTRIC and GnCenergy lead on directness. Once price and flow are included, the ranking changes.

The current order is LG Electronics, Iljin Electric, Samsung SDS, GST and SK Gas.

The next returns are likely to depend less on whether a company can tell an AI data-center story and more on three questions: Is there a contract? Is durable capital buying? How much is already in the price?

Sources

Price and flow data come from the Korea Invest Insights local database, Naver FChart and Kiwoom REST ka10059. This report is for research and information only and is not investment advice.

Real Money Flow on Korea Invest Insights