Samsung SDI's US battery JV cut its guaranteed debt 45% — the same year it turned its first profit
Samsung SDI cut its guarantee on StarPlus Energy's debt from $3.85bn to $2.11bn (−45.2%), the same filing showing the Stellantis battery venture's income swing from a ₩33.7bn loss in 2024 to a ₩123.1bn profit in 2025.
AI-assisted, human-reviewed sourcing. Figures are pulled programmatically from the official sources listed at the end of this article and checked by an editor before publication.
samsung sdistarplus energystellantisbatterydebt guaranteekorean equities
On 4 September 2026, Samsung SDI’s board revised a debt guarantee for StarPlus Energy LLC, its electric-vehicle battery joint venture with Stellantis, first disclosed on 13 December 2024. The revision cuts both the underlying debt and Samsung SDI’s guarantee of it by the same proportion — 45.2% — while the venture’s own disclosed financials show its first profitable year.
The revision, in the company’s own figures
| Item | Original (2024-12-13) | Revised (2026-09-04) | Change |
|---|---|---|---|
| Total debt (StarPlus Energy) | $7,540,752,378 | $4,132,257,708.66 | −45.2% |
| Samsung SDI’s guarantee (51% stake) | $3,845,783,714 | $2,107,451,432 | −45.2% |
| Guarantee, won-converted | — | ₩2,865,080,221,015 | — |
| Guarantee as % of Samsung SDI’s equity | — | 12.16% | — |
| Guarantee period | — | 2026-09-04 to 2035-12-15 | — |
The guarantee stays at exactly 51% of the debt before and after the revision — Samsung SDI’s ownership share in the joint venture is unchanged; only the total borrowing being guaranteed has moved. The filing states the reduced debt and guarantee figures without giving a reason for the change.
What StarPlus Energy’s own numbers show
The filing carries a summary of the debtor’s financial condition, on a year-end basis:
| StarPlus Energy LLC (₩bn) | 2023 | 2024 | 2025 |
|---|---|---|---|
| Total assets | 1,798.7 | 7,607.8 | 7,711.6 |
| Total liabilities | 183.0 | 5,242.4 | 5,291.8 |
| Total equity | 1,615.7 | 2,365.4 | 2,419.8 |
| Revenue | — | 56.3 | 931.1 |
| Net income | −30.2 | −33.7 | 123.1 |
Revenue rose from ₩56.3bn to ₩931.1bn — a roughly sixteen-fold increase — as the plant moved from pre-production (no revenue recorded in 2023) toward output. Net income turned from a ₩33.7bn loss to a ₩123.1bn profit over the same one-year span, the first profit the disclosed figures show for the venture.
The debt-guarantee cut and the swing to profitability appear in the same filing but the filing does not state that one caused the other; that connection is not made here.
What triggered the search interest this piece was written to answer
A same-day Google Trends spike (search volume 500+) on 2026-09-05 attached Samsung SDI’s name to a headline reporting a share-price gain on “domestic ESS market expansion” expectations. This piece could not verify that share-price move: the Korea Exchange’s own data site returned a service-unavailable error on both 2026-09-04 and 2026-09-05, and no other same-day price source was substituted. Readers arriving from that search will not find the stock-move figure confirmed here — what is confirmed, from Samsung SDI’s own DART filings, is the debt-guarantee revision and StarPlus Energy’s turn to profit described above.
This is a record of what was filed with DART, not investment advice.
Data & Verification Notes
- Data as of
- Sources
- Financial Supervisory Service (Korea, Open DART) — list.json + document.xml, corp code 00126362 — 타인에 대한 채무보증 결정 (debt-guarantee decision), rcept_no 20260904800510
- Financial Supervisory Service (Korea, Open DART) — Same filing's referenced prior disclosure — another 타인에 대한 채무보증 결정 (debt-guarantee decision), rcept_no dated 2024-12-13 (cited within the 2026-09-04 filing as the original decision being revised)
- Cross-checks
- The filing is itself a revision of a 2024-12-13 debt-guarantee decision for the same debtor (StarPlus Energy LLC) and creditors (U.S. Department of Energy, U.S. Federal Financing Bank) — read from the referenced-disclosures line inside the 2026-09-04 filing, not assumed
- Samsung SDI's revised guarantee amount is exactly 51.00% of the revised total debt ($2,107,451,432 / $4,132,257,708.66) — matching the same 51% stake ratio implied by the original 2024 figures ($3,845,783,714 / $7,540,752,378 = 51.0%), an internal consistency check across the old and new numbers
- The filing's own KRW conversion checks out: $2,107,451,432 × ₩1,359.50/$ (the rate stated as the board-resolution-date reference rate) = ₩2,865,080,221,804, matching the filed KRW guarantee figure of ₩2,865,080,221,015 to within rounding
- The new guarantee is 12.16% of Samsung SDI's own equity (₩23,570,113,159,830, stated as year-end-2025 basis) — the filed disparity-to-equity ratio, not separately computed here
- Excluded figures
- The 'domestic ESS market expansion' narrative that a 2026-09-05 Google Trends spike (search volume 500+) attached to Samsung SDI, sourced from a news headline about a same-day share-price move. That move could not be independently verified here — Korea Exchange's own site (data.krx.co.kr) returned a service-unavailable error on two separate checks (2026-09-04 and 2026-09-05), and no alternative same-day price source was used. This piece does not claim or repeat that stock-move figure.
- Whether StarPlus Energy is an ESS (energy storage system) plant or an EV-battery plant. Public reporting describes StarPlus Energy as Samsung SDI's electric-vehicle battery joint venture with Stellantis in Kokomo, Indiana — a different battery end-market from grid-scale ESS. This piece does not conflate the two; readers looking for the ESS story specifically will not find it answered here. Checked and not found within DART's structured filings for this corp code in the 2026-08-01 to 2026-09-05 window
- Why the debt amount was renegotiated down. The filing states the change and the resulting guarantee amount but gives no narrative reason (e.g., refinancing, construction-cost revision, loan restructuring). Checked and not found in the filing text
- The other counter-guarantees making up StarPlus Energy's ₩3.96tn total guarantee balance. That total is disclosed as excluding this filing's own revised amount, but the filing does not break out who holds the rest (co-guarantor Stellantis's own guarantee share is not disclosed here)
- Instruments
- 006400
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