Samsung SDI Q1 2026: Ex-Credit Losses Narrowed, but the Battery Segment Bridge Stays Blank

Decomposition Table

USD equivalents use FRED DEXKOUS quarterly averages: Q2 2025 ₩1,399.82, Q3 2025 ₩1,386.95, Q4 2025 ₩1,448.76, Q1 2026 ₩1,465.57.

† Consolidated figure from KRX preliminary-results filings. Samsung SDI does not allocate AMPC to its battery segment. The ex-AMPC row is editorial arithmetic (reported consolidated OP minus disclosed consolidated AMPC), not a company-provided adjusted figure.

‡ Samsung SDI does not disclose quarterly utilization, ASP direction, EV/ESS revenue mix, or battery-segment AMPC allocation in its English earnings materials or KRX filings. No TrendForce or other third-party quarterly estimate was available for Q4 2025 or Q1 2026 in the materials reviewed. The latest public utilization datapoint is the 2025 annual figure of approximately 50%.

Sources: Samsung SDI English earnings releases for Q2 2025, Q3 2025, Q4 2025, Q1 2026 (battery-segment figures); KRX KIND filings for each quarter (consolidated AMPC). Korean-language earnings call transcripts were not reviewed.

Pass 1: 45X Isolation and the Disclosure Penalty

Issue #4's decomposition left Samsung SDI's AMPC line blank because the English IR materials don't quantify it. That was incomplete. The KRX preliminary-results filings carry a consolidated AMPC figure every quarter. Four quarters now: ₩66.4B, ₩19.5B, ₩79.8B, ₩80.5B.

The Q3 2025 drop to ₩19.5B is worth isolating. A 71% QoQ decline, coinciding with Samsung SDI's worst quarterly battery loss (₩630.1B) and a Q3 release citing US tariffs on ESS batteries and slower EV sales. Whether this reflects lower US production volumes, a recognition timing shift, or an eligibility change cannot be resolved from English-language filings.

What happened next is more useful. Consolidated ex-credit losses narrowed ₩374.7B from that Q3 trough to Q1 2026. The Q4-to-Q1 move, ₩142.9B of narrowing, arrived on essentially flat AMPC (₩79.8B to ₩80.5B). The improvement was almost entirely operational. Clean.

What remains unresolvable: how the ₩80.5B splits between battery and electronic materials. Samsung SDI's electronic materials division reported ₩21B in operating profit in Q1. Bound the allocation. If the entire ₩21B were AMPC-derived, at least ₩59.5B accrues to battery, implying a battery ex-credit loss no better than approximately ₩236B. If electronic materials captured none, the battery ex-credit loss sits at approximately ₩257B. That ₩236B-to-₩257B range is a bound, not an estimate. I am not constructing the allocation Samsung SDI chose not to disclose. But the bound confirms the battery segment was deeply unprofitable on an ex-credit basis regardless of where the AMPC sits.

Place this next to LGES and the information asymmetry becomes concrete. LGES's Q2 2026 preliminary showed an ex-credit operating loss of ₩127.7B, narrowed from ₩397.6B in Q1, with production incentives disclosed at a level permitting a clean segment bridge. (Disclosure-quality comparison, not same-quarter financials; Samsung SDI Q1 is latest available, LGES Q2 is latest available.) Samsung offers no equivalent bridge. LGES's credit dependency is legible. Samsung's is not. LGES therefore looks more dependent on 45X partly because it shows the dependency. Do not read Samsung's opacity as evidence of better underlying health. It is evidence of less information.

Practical consequence for procurement: asymmetric confidence. LGES's underlying trajectory is trackable quarter by quarter with disclosed figures. Samsung SDI's consolidated direction is visible, improving, but the segment-level mechanism producing that improvement is not. Same signal, different resolution.

Pass 2: Utilization and Mix

Samsung SDI has not disclosed a quarterly utilization figure for Q4 2025 or Q1 2026. No TrendForce estimate for these periods appeared in the materials reviewed. The latest public datapoint remains the 2025 annual figure of approximately 50%, per Seoul Economic Daily. LGES was 47.6% and SK On 48.7% on the same annual basis.

Battery-segment revenue rose 19% from the Q3 trough (₩2,820B) to Q1 (₩3,354B) over two quarters. If ASPs were flat or declining (Samsung does not disclose ASP direction), that revenue increase implies higher volumes, which would imply utilization running above the 2025 annual average. This is inference from revenue, not a disclosed utilization figure, and it carries the weight that label implies.

The denominator question compounds the uncertainty. Samsung SDI has not specified whether its capacity base changed through rationalization or through ramp of new lines at StarPlus, as covered in Issue #4. Utilization can improve because the numerator rises or because the denominator shrinks. Without either number, you cannot distinguish capacity discipline from demand recovery.

Samsung SDI also does not disclose EV/ESS revenue mix. The Q1 release describes growth across ESS, UPS, BBU, power tools, and high-value cylindrical batteries, attributing improvement partly to expanded US ESS production and sales. The Q4 2025 release called ESS batteries the highest quarterly revenue on record. These are qualitative directional signals. ESS share is growing. What the share actually is, and therefore whether the revenue recovery is EV-led, ESS-led, or both, cannot be determined from the available data.

The rate of change in utilization is doubly obscured: no numerator, no denominator. Revenue trajectory suggests improvement. Magnitude and channel remain blank.

Pass 3: Guidance vs. Actuals and ESS Execution

Samsung SDI's Q4 2025 release guided toward improvement beginning in Q1 2026, with quarterly profitability targeted for H2 2026. Seoul Economic Daily reported Samsung expected ESS battery sales to expand by 50% in 2026, weak first half, strong second half.

Q1 delivered on the directional guidance. Consolidated losses narrowed from ₩299.2B to ₩155.6B. The Q1 release attributed improvement to increased AMPC benefits from expanded US production and ESS battery sales growth, reiterating the H2 profitability target. No numeric Q2 guidance.

Now the execution evidence. Samsung SDI's Q4 2025 IR deck guided "full capacity sales of ESS prismatics" at 20 GWh and US local mass production of SBB 2.0 (prismatic LFP) in Q4 2026. StarPlus Plant 1's NCA ESS line has been operational since October 2025 per Issue #6 coverage. LFP lines are not yet producing accepted output based on the materials reviewed. Samsung SDI has signed an LFP cathode supply agreement with L&F for StarPlus; terms are covered in the sidebar. No named US ESS counterparties appear in the reviewed English earnings materials. No converted-line GWh, yield data, or customer acceptance documentation has been disclosed.

This is the familiar gap between narrative and evidence at this stage of conversion. Korean LFP timelines typically run 3–5 years from pilot to stable yields. Samsung SDI is attempting to compress that. The H2 profitability target rests on execution milestones (LFP line qualification, SBB 2.0 ramp, customer acceptance) that have been guided but not yet evidenced in public filings. Two consecutive quarters of directional improvement from the Q3 trough lend credibility to the trajectory. Whether that trajectory reaches profitability in H2 depends on variables Samsung SDI has described but not yet shown.

Sourcing Decision Frame

Samsung SDI's risk profile improved this quarter on direction and deteriorated on visibility relative to LGES. Operational trajectory is the best in four quarters: battery-segment losses more than halved from the Q3 trough, consolidated ex-credit losses continued narrowing on stable AMPC, and ESS revenue is qualitatively described as growing. The prismatic form factor gives Samsung SDI a structural position with BESS buyers who specifically require it, though many US integrators have historically been format-agnostic, which limits the moat's practical width to a subset of procurement decisions.

For a team evaluating Samsung SDI as a FEOC-compliant ESS supplier, the operational trajectory supports continued engagement. The disclosure trajectory does not support the same confidence you can place in LGES's equivalent numbers. That asymmetry is not disqualifying. It is a reason to assign wider uncertainty bands to Samsung SDI's underlying health and to weight the July 30 Q2 release heavily. If Samsung begins allocating AMPC to the battery segment, the information gap closes. If it doesn't, the disclosure penalty compounds as LGES's bridge gets cleaner quarter by quarter, and the two suppliers' risk profiles diverge on legibility even if their underlying economics are converging.