X-FAB Silicon Foundries SE
Cheap assets, empty fabs: the photonics option costs little but pays late

Research date: 22 October 2026. Company: X-FAB Silicon Foundries SE. Listing: Euronext Paris, XFAB (US OTC XFABF). ISIN: BE0974310428. Financial reporting currency: USD (IFRS); the share trades in EUR. Latest financial period reviewed: six months ended 30 June 2026 (half-year report 1 September 2026). Material announcements reviewed through 22 October 2026. Capture window 17:30 to 20:05 Europe/Luxembourg.

Tags used throughout: confirmed = company filing, release or primary source; est. = our arithmetic from confirmed inputs; speculated = sell-side, vendor report or social post. Every figure carries the source's own date; broker rows carry a capture timestamp as well.

Idea origination: why we are researching Serenity's XFAB thesis

This idea came onto our research agenda through Serenity (@aleabitoreddit), the same account whose Sivers thesis we examined. On 27 May 2026 he posted that "$XFAB (photonics + power semis) is an interesting long idea at $1.28B MC, that I took positions in", citing about 1.29× price to book, a "6.5 to 8.5 forward P/E 2028 personal estimate", the EU Chips Act grant, a silicon photonics evaluation "with $NVDA" via the photonixFAB project, "the only high-volume SiC foundry in the US", and Navitas and Power Integrations as SiC customers (the post, text recovered via search snippets because x.com returns 402 to fetch tools). The stock rose as much as 76% intraday that day to a record EUR 15.88 (Reuters via LSE; Bloomberg); the CEO told Reuters by email that the company "is not aware of any undisclosed material developments". Independent trackers: Serenity Tracker universe (XFAB conviction 8 of 10, added 27 May 2026). Serenity gets credit for the idea; filings set the baseline; this memo supplies the evidence checks. We do not assert an audited performance record or his current position.

Investment memo: our current view

Asset-value watchlist; the growth legs are a 2028 option. X-FAB is a European specialty foundry whose core business is shrinking: automotive wafers, 58% of sales, fell 19% year on year in Q2 2026, utilisation is about 60% against an 85 to 90% target, the backlog has fallen for four straight quarters, and the December 2024 targets (2026 revenue USD 1.05B at a 30% EBITDA margin) were withdrawn in February 2026 with nothing put in their place. Reported EBIT was USD 2M a quarter in the first half of 2026.

The thesis segment, silicon photonics, generated about USD 6 to 7M in 2025 (8% of prototyping revenue, est.), has no separately disclosed dollar line, and is guided to volume production in 2028. No X-FAB filing, release or call names Nvidia or Nokia; the only trace is imec's 2024 consortium page listing them as application partners of the EU-funded photonixFAB project. The public photonics partners are LIGENTEC and SMART Photonics. Tower's silicon photonics run rate is already about 100× X-FAB's photonics revenue.

What survives of Serenity's case is the asset side, and it is stronger today than when he posted: at EUR 5.14 (22 October 2026 close) the shares trade at 0.75× book, the enterprise value of about USD 1.09B is below the USD 1.1B spent on capacity in 2023 to 2025, there has been no dilution since the 2017 IPO, and grants (EUR 127.4M Erfurt, up to USD 50M Lubbock proposed) fund the next capex. External anchors all sit above the price: Morningstar quantitative 5 stars with a fair value of EUR 8.44, LSEG consensus Buy on 7 analysts with a EUR 7.74 target, TipRanks EUR 9.40. But five of the seven analysts are Hold, ISS EVA moved to Underweight on 5 October 2026, Morningstar assigns no moat and places three-year EBIT growth in the bottom 1% of peers, and 2026 EPS consensus is about zero. Net debt of USD 312M includes USD 255M of loans classified current against USD 164M of cash, so the revolving facility renewal is a 2026 item.

Our scenario values today are EUR 3.1 bust, EUR 9.5 base, EUR 20.8 boom (12% discount rate, four years). The price sits between bust and base, closer to the bust path, which is also the consensus path. The next hard test is the Q3 2026 report on 29 October 2026: revenue USD 195 to 205M, EBITDA margin 17 to 20%, and, for "H1 was the bottom" to hold, order intake above about USD 200M.

Thesis underwriting: from source idea to investable conclusion

Listing and timestamps

What the business actually sells

X-FAB is a pure-play specialty foundry: it fabricates wafers for fabless customers and designs no products of its own. Three business units since 2025: Smart CMOS & SOI (analog/mixed-signal, BCD-on-SOI, 1.0 µm to 110 nm, 200 mm), Microsystems & Photonics (MEMS sensors, microfluidics, piezo, AlN, wafer-level packaging; silicon photonics revenue reported inside this unit from Q1 2026), Wide Bandgap (SiC on 150 mm at Lubbock, GaN from Q1 2026). Six fabs: Erfurt (DE, converting from CMOS to the microsystems and photonics hub), Dresden (DE, 200 mm CMOS), Itzehoe (DE, MEMS), Corbeil-Essonnes (FR, 200 mm CMOS, ex-Altis), Lubbock (TX, SiC), Kuching/Sarawak (MY, 200 mm CMOS, the 2023 to 2025 expansion; 40,000 wafer starts a month fully operational by end 2026). Confirmed, AR 2025 and Q4 2025 release.

Revenue by end market (USD M, excl. IFRS 15 over-time effect), confirmed, Q2 2026 release 30 Jul 2026

Revenue by technology (USD M, excl. IFRS 15), confirmed

FY2025 technology lines use the old split (CMOS, Microsystems, Silicon carbide) from the Q4 2025 release; quarterly sums match the annual totals.

• Photonics today: three silicon photonics projects with key partners were 8% of 2025 prototyping revenue (confirmed, AR 2025). 2025 prototyping revenue was about USD 83M (sum of quarterly prototyping lines, est.), so photonics revenue 2025 ≈ USD 6 to 7M (est.). Q1 2026 was the first report to fold photonics (and GaN) into the reported lines: Microsystems & Photonics jumped to USD 33.7M from USD 25.0M in Q4 2025 when photonics was added, then fell to USD 28.7M in Q2, so the photonics contribution is a low single-digit USD M a quarter (est.); no separate photonics dollar figure is disclosed. Platform: 200 mm XPH90 SOI photonics with Ligentec SiN and TFLN, laser chiplets from SMART Photonics (secondary, PhotonCap). Volume production expected 2028 (confirmed, Q2 2026 release); KBC expects material revenue from 2027 (speculated). Nvidia and Nokia are application-developer participants in the EU-funded €48M photonixFAB consortium that X-FAB leads (confirmed, CORDIS 101111896, optics.org); no commercial SiPh supply agreement with either is disclosed.
• Data center: management puts current data-center revenue at USD 20 to 30M a year across CMOS, SiC and sensors, and long-term potential at about USD 300M a year (confirmed as management statement, Q2 2026 call and release). Three SiC data-center design wins in Q2 2026.
• SiC: FY2025 SiC revenue USD 33.8M, −34% YoY (confirmed); Q4 2025 SiC wafer starts +60% QoQ with lower billings because customers now supply their own SiC substrates (confirmed). The US Department of Commerce calls Lubbock "the only high-volume SiC foundry in the U.S." (confirmed as Commerce wording, 6 Dec 2024). Customers named by Serenity: Navitas, Power Integrations (PCN-22181), Lite-On (speculated; not in X-FAB filings).
• Customer concentration: Melexis 43% of 2025 revenue, top 3 53%, top 5 58% (confirmed, AR 2025). CEO Rudi De Winter (ex-Melexis CEO) handed over to Damien Macq on 6 Feb 2026 (confirmed).
• Bookings and backlog: Q2 2026 order intake USD 173.3M (+2% QoQ), backlog USD 291.8M (−5% QoQ), book-to-bill above 1 ex Erfurt end-of-life for the first time since Q2 2024 (confirmed). FY2025 bookings USD 709.2M, −19%.
• Utilisation: about 60% at Q2 2026 against an 85 to 90% target (confirmed, Q2 slides via Investing.com). Capacity in place for about USD 1.2B annual revenue (confirmed, Investor Day 2025).
• Capex: USD 1.1B over 2023 to 2025 (confirmed); FY2025 USD 204.1M; 2026 about USD 100M net of grants; capex ratio 10% of revenue for a few years, then 15% (confirmed, Q4 2025 release and Investor Day).
• Guidance: Q3 2026 revenue USD 195 to 205M, EBITDA margin 17 to 20%, at 1.14 USD/EUR, excl. IFRS 15; no FY2026 guidance (confirmed). Cost savings USD 6M a quarter by Q4 2026.
• Grants: EU Chips Act €127.4M for Erfurt Fab4Micro (€80.3M federal, €47.1M Thuringia; notification 23 Jun 2026; initial production end 2028) (confirmed). US CHIPS non-binding PMT up to USD 50M for Lubbock, 6 Dec 2024 (confirmed as PMT; no final award found). Serenity's "$128M euros" and "EU Chips Act 2" inclusion are rounding and a guess respectively; Chips Act 2 was proposed 3 Jun 2026 and is not law (secondary).

Where the wafer sits: one campus, one EV, and the money that reaches X-FAB

Silicon photonics chain (the thesis segment)

End customer: hyperscaler AI campus, 1 GW, about USD 40B all-in (est., from the SIVE ladder) ⊃ GPU rack: NVIDIA NVL72-class, USD 3 to 4M, built by Foxconn, Jabil, Dell (confirmed/est.) ⊃ optical module: 1.6T transceiver, USD 1,500 to 2,000, 3 to 4 per GPU, from Innolight, Eoptolink, Coherent, Jabil (est.) ⊃ photonic IC: two silicon photonics PICs per module, about USD 70 of a USD 341 bill of materials, so about USD 35 per PIC (secondary, PhotonCap) ⊃ the foundry wafer: PICs today come from Tower, GlobalFoundries and TSMC; X-FAB's XPH90 is at NRE stage with volume in 2028 (confirmed). The wafer-fab step is 30 to 40% of a PIC's component cost (secondary), so about USD 10 to 14 of foundry value per PIC ⊃ substrate: photonic SOI wafer from Soitec, about USD 1,300 per 200 mm-equivalent wafer (secondary, Ozeco via PhotonCap).

Money ladder, one 1 GW campus, if X-FAB were the sole PIC foundry (est.)

One campus fully won ≈ 6 to 8 years of X-FAB's current photonics revenue, and about 5% of group revenue. Even a full campus is small against the USD 870M group; the photonics case needs several campuses a year and a 2028 start. Tower's SiPh run rate is already above USD 680M (confirmed, Q2 2026), roughly 100× X-FAB's photonics revenue.

SiC chain (the other growth leg)

EV buyer ⊃ 800V EV, ~USD 45k ⊃ traction inverter, USD 2,000 to 3,000 ⊃ SiC MOSFET set, ~48 dies, USD 500 to 700 of device value (est.) ⊃ X-FAB foundry processing on a customer-supplied 150 mm SiC substrate, about 40% of device value, USD 200 to 300 per vehicle (est.) ⊃ substrate: Wolfspeed, Coherent, SICC. One million EVs fully won ≈ USD 200 to 300M ≈ 6 to 9 years of 2025 SiC revenue (USD 33.8M). Current SiC customers are mostly industrial and data-center power, not traction (confirmed: Q2 2026 release cites 800V data-center power).

The financial starting point

H1 2025 EBIT (42.8) and net income (11.8) are the HY 2026 report comparatives (confirmed); H1 2025 EBITDA is derived from the Q1/Q2 2026 YoY declines (est. ±1). Q2 2026 net loss includes USD 11.0M non-cash deferred-tax derecognition in Malaysia. Net debt rose USD 26M in H1 2026, including USD 18.9M repayment of long-term-agreement prepayments; free cash flow was about −USD 25M (est.). Customer prepayments and capacity deposits of USD 292M funded part of the 2023 to 2025 capex (confirmed, Investor Day) and are being repaid as wafers ship; USD 53.0M falls due after 12 months (confirmed, HY 2026). Covenant: net debt ≤ 3× EBITDA (3.5× in defined cases) per the Q2 2026 slides; the 2025 annual report adds that no additional borrowing is permitted if net indebtedness exceeds 4× EBITDA, and reports compliance at 31 Dec 2025; at Q2 2026 trailing EBITDA (~USD 165M) the ratio is about 1.9× (est.). A €200M revolving facility is being extended one year and a Schuldschein is under consideration (confirmed, Q2 slides).

Where X-FAB stands today: inputs reused in the sections below

Competitors and market share (22 October 2026)

1a. Silicon photonics (SiPh) foundry: who can make a photonic IC wafer for a third party

Estimated 2026 SiPh foundry revenue. "Same thing" = sells SiPh PIC wafers to merchant customers as X-FAB intends to.

Read-across: the merchant SiPh foundry market in 2026 is roughly Tower + GF + ST ≈ USD 1.8 to 2.2B (est., sum of the three disclosed or guided lines on a wafer basis). X-FAB's share is ~0%. Every 300 mm competitor adds capacity in 2027 to 2028 (Tower Arai, GF New York/Singapore, ST Crolles to 20k wpm, UMC P4, Samsung), which PhotonCap flags as a possible glut exactly when X-FAB's 200 mm volume is due to start (2028).

1b. SiC foundry and merchant power SiC

Open-foundry SiC (make wafers for fabless power customers) is a tiny niche; most SiC revenue is IDM device sales. Ranges are vendor or sell-side estimates for calendar 2025 SiC device revenue unless stated.

1c. Core business: specialty analog, mixed-signal, MEMS foundry

X-FAB is a sub-scale (about half of Tower, a tenth of UMC) specialty foundry with 60% utilization and a 43% single-customer exposure (Melexis, AR 2025). Its differentiation is automotive qualification and the European location, not cost.

Addressable market under two anchors

2a. Merchant SiPh foundry

Share X-FAB would need for its 2030 photonics revenue in the scenarios below (the same revenue paths are used for the per-share values in the valuation section): bust USD 40M = 0.6 to 0.8% of anchor B 2030; base USD 120M = 1.7 to 2.4%; boom USD 450M = 6 to 9% (and ~30% of the 200 mm-only slice, since all big expansions are 300 mm).

2b. SiC

X-FAB's USD 40 to 50M wide-bandgap line is already ~15 to 30% of the open SiC foundry pool (est.), so the SiC case is a market-growth and data-center (800 V DC) story, not a share story. Its 150 mm line is a cost disadvantage versus 200 mm IDMs.

Scenarios: 2030 revenue under bust, base and boom (22 October 2026)

Consensus (MarketScreener, 7 analysts, USD M, read 2026-10-22; stockanalysis.com shows the same 2026 mean in EUR terms with 7 analysts, range 803 to 845): 2026 817.8, 2027 902.2, 2028 990.1 (EBITDA 160.8 / 213.2 / 256; net income −10 / 32 / 68; net debt 339 / 368 / 316). Houses with dated calls found: Bernstein Outperform, EUR 13 (raised from 12.80 on 2026-09-30, IBKR analyst log); Kepler Cheuvreux Buy, EUR 10.50 (2026-07-06); Deutsche Bank Hold, EUR 6.00 (2026, raised from 4.60); Berenberg Hold, EUR 6.00 (2026-05-05). Target range EUR 4.42 to 13.05, mean 7.70 (stockanalysis, 2026-09-08). Not found: KBC Securities, Degroof Petercam, ODDO BHF notes (likely exist as Belgian/French coverage; needs a terminal or the IBKR pull). Fintel page not found.

Revenue per wafer sanity check (est.): USD 870M / (100k × 12 × ~0.7 utilization 2025) ≈ USD 1,000 per 8-inch-eq wafer; SiPh wafers at USD 4 to 5k are 4 to 5× that, which is why photonics mix matters more than its wafer count.

Valuation: market data and scenario values as of 22 October 2026

Multiples

Replacement-cost argument. EV of about USD 1.09B is below the USD 1.1B the company spent on capacity in 2023 to 2025 and below net PP&E of USD 1.2B, while utilisation is 60%. The market is pricing the assets as under-earning, which they are: EBIT was USD 2M a quarter in H1 2026. The argument only pays if utilisation recovers toward the 85 to 90% target; the Investor Day showed about 60% fixed costs, so each 10 points of utilisation is worth roughly USD 60 to 80M of EBITDA (est.).

Consensus houses. Seven analysts (StockAnalysis, MarketScreener), mean target €7.70, rating Buy/Outperform. Named calls (per the leadership fork's broker register): Bernstein Buy/Outperform €13 (raised from €12.80 on 30 September 2026 per the IBKR analyst log; June 2026 initiation by Aleksander Peterc, who called the photonics rally "premature at best" and rests the case on automotive recovery, wide-bandgap and BCD-on-SOI); Kepler Cheuvreux Buy €10.50; KBC Hold €8.8 (photonics revenue material from 2027); Deutsche Bank Hold €6.00; Berenberg Hold €6.00. Investing.com's 8-analyst mean of €5.53 disagrees with the others and could not be reconciled. Management's December 2024 targets (2026 revenue USD 1.05B, 30% EBITDA margin) were abandoned in February 2026 and replaced by no FY2026 guidance.

Dilution history. None since the April 2017 IPO: share count unchanged at 130.78M issued, no convertibles, no option overhang (confirmed, AR 2025, HY 2026). Financing has come from debt (gross USD 476M), customer prepayments (USD 292M in 2023 to 2025) and grants (USD 10M in 2025; €127.4M Erfurt to come). Major holders: Elex NV 24.98%, Sensinnovat BV 24.91% (Duchâtelet and De Winter vehicles; Xtrion no longer holds X-FAB), Sarawak Technology Holdings 11.43%, public 38.7% of 130.78M shares. No dividend.

Scenario values (2030 EBITDA × multiple, less net debt, per share, discounted 4 years at 12%)

At €5.14 the price sits between bust (€3.1) and base (€9.5), closer to the bust path, which is also the consensus path. Scenario revenues are the same as in the scenarios section (aligned in the 22 Oct 2026 fact audit; EBITDA margins 19 / 25 / 28%). Serenity's "6.5 to 8.5× forward P/E 2028" at his €9.9 entry implies 2028 net income of USD 170 to 220M (est.), 5 to 7× the 2027 consensus of USD 32M and above the 2025 peak-cycle EBIT; that is a boom-case earnings path, not a base one. His own takeout-free thesis (low P/B, grants fund capex, SiPh optionality) is intact on the asset side; the earnings side is unproven until utilisation moves.

Broker and ratings data, IBKR Mobile, captured 2026-10-22

Known gaps of this read-only pull

• Live quote IS available for Euronext Paris (unlike Stockholm for SIVE), but the session was closed (Outside RTH) at capture.
• No events / earnings-date tab for this listing; Q3 2026 results date must be taken from the company calendar on the web.
• Short interest as % of float is not shown; only IBKR shortable shares and borrow fee.
• Annual and quarterly LSEG forecast values are read off bar charts (approximate, +/-5%); only the headline numbers (EPS 0.23, EBIT 76.42M, EBITDA 196.83M, revenue 870.26M, capex 204.13M, net debt 286M, BVPS 8.06, gross margin 21.19%) are exact labels.
• Morningstar full quantitative report PDF was not downloaded.
• Analyst Action Log (Briefing/StreetInsider) not captured.
• Financials tab (statement detail) not captured; only the Company summary tiles.

Read-across

• Price 5.13 EUR vs Morningstar quant FVE 8.44, LSEG target 7.74 (median 6.16), TipRanks 9.40: every external anchor sits above the price, the opposite of SIVE.
• But consensus is 'Hold'-heavy (5 of 7), ISS EVA moved to Underweight on 5 Oct, Morningstar flags no moat and bottom-1% EBIT growth, and 2026 EPS consensus is about zero.
• Serenity's 'below replacement P/B' claim: BVPS 8.06 USD (~7.0 EUR) vs 5.13 EUR price gives P/B ~0.7x; consistent with IBKR data.
• The 5 Oct Fab4Micro release confirms EUR 127.4M of EU Chips Act funding for Erfurt microsystems/photonics capacity; it names automotive/industrial/medical, not AI data-centre photonics.
• Next hard test: Q3 2026 results against guidance of $195-205M revenue and 17-20% EBITDA margin (date not shown in IBKR).
• Emulator shut down and IBKR force-stopped at 18:53.

Leadership and governance: the CEO, the families, the letters and the order book (22 October 2026)

Captured 2026-10-22T18:47+0200 Europe/Luxembourg. Listing: Euronext Paris XFAB (Belgian SE, HQ Tessenderlo-Ham). Price at capture: EUR 5.14, market cap ~EUR 671M, 130.6M shares (stockanalysis.com, 22 Oct 2026 17:35 CEST, delayed). 52-week range EUR 4.09 to 15.88 intraday (Option Finance reported the 15.88 high on 27 May 2026, consistent with Reuters' EUR 2.06B peak cap; the 12.20 some vendors show is a closing-price basis).

Tags: confirmed = company release or filing; secondary = data vendor or press; est. = our arithmetic; gap = not found.

Who runs it

Ownership, Xtrion and related parties

• Until Nov 2023 the Duchâtelet and De Winter-Chombar families controlled X-FAB jointly through Xtrion NV (48.3% after the 2017 IPO; 61% pre-IPO). On 14 to 20 Nov 2023 Xtrion transferred all shares to its two indirect owners and the Xtrion-Sarawak shareholder agreement was terminated. Xtrion now holds 0 shares. Same day, Xtrion sold its Melexis stake the same way, ending joint control there too. (confirmed: company releases 14 and 20 Nov 2023; Melexis release)
• Register (company transparency table, undated post-Nov 2023; MarketScreener current): Elex NV / Duchâtelet Future Private Foundation 24.98% (32.67M shares), Sensinnovat BV (De Winter-Chombar) 24.91% (32.57M), Sarawak Technology Holdings (State of Sarawak) 11.43% (14.95M), public 38.7%. Total 130,781,669 shares. No single controller; the two family blocks are just under 25% each, so a 25% threshold notice would flag any top-up.
• Related-party dealing on record: Jan 2024 X-FAB bought M-MOS (SiC MOSFET IP) from Xtrion for EUR 22.5M (semiconductor-today, 5 Jan 2024). Buying an asset from the controlling families' vehicle is the one transaction to read in the related-party note of the 2025 annual report (gap: note not extracted; ESEF file too large for the fetch tool).
• Melexis link: Macq came from Melexis; De Winter and Chombar (Melexis CEO to 2022) and Duchâtelet founded both. Melexis is historically a large X-FAB customer. Its share of 2025 revenue is 43% (top three customers 53%, top five 58%; AR 2025 risk factors). Melexis is described in the AR as a former related party (joint control ended Nov 2023); the related-party sales figure itself was not extracted (gap).
• Controversies found: none personal. July 2020 Maze ransomware production halt (Wikipedia). No restatement, no auditor dispute found.

Promises vs delivery, last four results

Pattern: quarterly guidance is met on the "ex-IFRS 15" basis the company chooses, but the two multi-year targets (2026 USD 1.05B / 30%) were abandoned within 14 months, and EBIT has fallen from USD 23.8M (Q3 2025) to 2.1M (Q2 2026) under full fixed-cost load from the USD 1.1B capex programme. Note the Serenity thesis items (SiPh foundry capacity, Nvidia/Nokia evaluations) appear in no company release; the only named photonics customers are partners LIGENTEC (Jan 2026, XPH90 SOI platform sold via LIGENTEC) and SMART Photonics (InP-on-Si, prototyping mid-2026, ramp readiness 2027).

Revenue-quality test (foundry version)

Quality verdicts: (1) revenue is 93 to 94% automotive/industrial/medical production wafers, not AI; (2) ~USD 30 to 40M of 2025 bookings and the Q1 IFRS 15 swing come from last-time-buy 0.6µm CMOS ending early 2027 and from expired LTAs, so reported revenue overstates the going-forward base; (3) customer concentration: Melexis 43% of 2025 revenue, top five 58% (AR 2025); releases only mention "one major SiC customer"; (4) the "USD 300M/yr AI data-centre potential" is a pipeline statement with no bookings attached.

Insider register (2024 to 2026)

No insider or family-vehicle sales were found for 2024 to 2026, including through the May to June 2026 spike (EUR 10 to 16). The De Winter-Chombar vehicle was a net buyer at EUR 6 to 7.5 in 2024. Pay: non-exec fee EUR 15k + 5k per committee; De Winter 2024 total ~USD 471k (Simply Wall St, secondary); 2026 AGM aligned the CEO's variable pay with other executives and added a long-term component (2026 proxy). Option plan sizes: gap.

Red flags

• Abandoned medium-term targets (Dec 2024 → Feb 2026) and no FY2026 guidance.
• Reported quality adjustments: every quarter is presented "ex-IFRS 15"; Q4 2025 had a USD 9.3M SiC one-off; Q2 2026 an USD 11.0M Malaysian deferred-tax derecognition (non-cash, but a statement about expected Malaysian profits).
• Leverage: net debt USD 312M against EBITDA run-rate ~USD 135M (est. 2.3×) and EBIT near zero; USD 255M of loans classified current at 30 Jun 2026. Covenants: no additional borrowing if net indebtedness exceeds 4× EBITDA (AR 2025, compliant at 31 Dec 2025); net debt ≤ 3× EBITDA (3.5× in defined cases) per Q2 2026 slides.
• Analyst stance: 7 analysts, consensus target EUR 7.70 (S&P: 7.48 on 4 Sep 2026). Deutsche Bank downgraded to Hold at EUR 6.00 (Dec 2025); Berenberg to Hold EUR 6.00 (5 May 2026); Bernstein Buy EUR 13 (raised from 12.8 on 30 Sep 2026; confirmed in the IBKR analyst log and TipRanks, captured 22 Oct 2026); Kepler Cheuvreux upgrade to Buy EUR 10.50 (Jul 2026). No short report found.
• Share price under Macq: ~EUR 6 to 7 at handover (Feb 2026) → spike to EUR 15.88 intraday on 27 May 2026 (record cap ~EUR 2.06B) → June 12 ~10.23 → July 2 ~7.22 → EUR 5.14 on 22 Oct 2026, below the pre-spike level and near the 52-week low of 4.09.
• The 27 May 2026 Serenity spike: Reuters: stock +76% intraday, +38% at 13:22 GMT, YTD +141%, second most traded on Tradegate after Micron; the post called X-FAB an "interesting long idea" tied to photonics and power semis. CEO Macq told Reuters by email the company "is not aware of any undisclosed material developments that would warrant disclosure at this time." No RNS was issued. The company's Q2 release two months later contained no photonics customer news beyond the Erfurt grant, which supports the CEO's statement and undercuts the "Nvidia/Nokia evaluation" claim.
• Restatements: none found. Auditor change: not found (renewal outcome gap). Delayed reports: none; Q2 published 30 Jul 2026 on schedule.

Next hard test

Q3 2026 results, Thursday 29 October 2026, 07:00 CET (one week from capture). Pass marks: revenue in USD 195 to 205M ex-IFRS 15 and EBITDA ≥17% and order intake above ~USD 200M (book-to-bill >1) to validate "H1 was the bottom". Also watch: any FY2026 guidance, the USD 6M/quarter savings run-rate, net debt direction, and whether photonics gets a named customer. Half-year report was due 1 Sep 2026.

Gaps to close from the 2025 annual report (ESEF, filings.xbrl.org, too large for fetch)

Related-party revenue figure; M-MOS purchase note; auditor renewal outcome; option plan size; director shareholdings. (Closed in the 22 Oct 2026 audit: Melexis 43%, covenants, auditor mandate.)

Serenity's claims versus the evidence

Serenity's post (X, 2026-05-27, status 2059537337324085541, recovered via search 2026-10-22). Note: the post says "the only high-volume SiC foundry in the US", not Europe; the brief's "Europe's only" wording is a paraphrase that drifted.

Net for the scenario section: order momentum is negative (backlog down four quarters, book-to-bill below 1, Dec 2024 targets abandoned), the first hard test is the Q3 report on 2026-10-29. Serenity's cheapness claim is stronger now (P/B 0.75, EUR 5.14) than when he posted; the growth claim remains a 2028 option on one consortium and unnamed power wins, with consensus 2028 revenue USD 990M (+14% on 2025). The boom case requires both a named photonics volume customer and Chips Act 2 money; neither has a date.

Fact audit: corrections made on 22 October 2026

Corrections applied on 2026-10-22

• BV: 52-week-high note rewritten (15.88 intraday confirmed, 12.20 closing basis).
• BV: H1 2025 EBITDA ~98 → ~101 (est.), margin ~23% → ~24%, EBIT ~41 → 42.8, net income ~24 → 11.8; footnote rewritten.
• BV: covenant note extended with the AR 2025 4× borrowing cap.
• BV: scenario table revenue 950 / 1,200 / 1,500 → 1,090 / 1,400 / 2,000; EBITDA 180 / 300 / 420 → 207 / 350 / 560; EV, equity, per-share and value-today rows recomputed; value today €2.5 / €8.0 / €15.5 → €3.1 / €9.5 / €20.8; closing sentence updated.
• CS: customer concentration 43.5% → 43% (Melexis), with top-three 53% added, source AR 2025 (two places).
• CS: X-FAB photonics revenue "≈ USD 2 to 4M est." → "≈ USD 6 to 7M" (8% of USD 83.2M prototyping).
• CS: "Q1 2026 report was the first to break out photonics" → "included in the Microsystems & Photonics line, no separate figure".
• CS: bust-scenario photonics row now states the 2025 base; TAM share paragraph notes the shared revenue paths.
• LD: 52-week range note rewritten; Melexis share gap closed (43%); Q4 2025 net debt ~285 est. → 286.1 confirmed; concentration verdict rewritten; covenant gap closed; auditor row expanded (reappointment date, fees); Bernstein target flagged as secondary-only; gap list trimmed.

Still open after the audit

• Bernstein target: closed by the IBKR pull (Buy, EUR 12.9 per Reuters 30 Sep 2026, EUR 13 on TipRanks).
• Closing price and date behind the €12.20 "52-week high" some vendors show.
• Final status of the US CHIPS USD 50M proposed award (no document after Dec 2024).
• Related-party revenue figure (Melexis), M-MOS purchase note, 2026 AGM auditor decision, option plan size, director holdings (AR 2025 ESEF text is extractable in raw/annual-report-2025.clean.txt, 2.16M characters, for a follow-up pass).
• POWI PCN-22181 naming X-FAB as foundry (document not retrieved).

What is still open

• Any X-FAB commercial SiPh supply agreement with Nvidia or Nokia (only consortium participation is documented).
• Navitas, Power Integrations and Lite-On as X-FAB customers (Serenity; not in filings).
• Final US CHIPS award for Lubbock (only the Dec 2024 PMT is documented).
• PIC cost per module and foundry share (single secondary source, PhotonCap).
• Related-party revenue figure (Melexis), the M-MOS purchase note, the 2026 AGM auditor decision, option plan size and director holdings, all extractable from the 2025 annual report text in the archive.
• The closing-price date behind the EUR 12.20 '52-week high' some vendors show.
• No events tab exists in IBKR for this listing; the 29 October 2026 results date comes from the company calendar.

Checkpoints that can change the view

• 29 October 2026, Q3 2026 results: revenue within USD 195 to 205M, EBITDA margin at or above 17%, order intake above about USD 200M; any FY2026 guidance; the USD 6M a quarter savings run rate; net debt direction; a named photonics customer.
• Revolving facility: EUR 200M extension and a possible Schuldschein; USD 255M of loans are current.
• US CHIPS: a final award for Lubbock would convert the December 2024 proposal.
• EU Chips Act 2: adoption targeted Q2 2027; a Strategic Project designation for Erfurt would be the boom-case trigger.
• Photonics: first disclosed photonics dollar revenue, a volume customer ahead of the 2028 date, or a Tower-style prepayment.

Information dates and future updates

Price and broker data are stamped 22 October 2026 (Europe/Luxembourg). Filings: annual report 2025 (30 March 2026), Q1 2026 release (30 April 2026), Q2 2026 release (30 July 2026), half-year report (1 September 2026), Fab4Micro groundbreaking release (5 October 2026). The review date for every record is 29 October 2026. Sources and retrieval hashes are listed in the published source manifest.

Sources read for the competitor and scenario sections

• X-FAB Q2 2026 slides and release, 2026-07-30: https://www.investing.com/news/company-news/xfab-q2-2026-slides-recovery-signals-emerge-despite-revenue-decline-93CH-4825806 ; https://finance.yahoo.com/markets/stocks/articles/x-fab-second-quarter-2026-154000891.html
• X-FAB Q4 2025 call summary: https://quartr.com/events/x-fab-silicon-foundries-se-xfab-q4-2025_F3RQKhuw ; https://seekingalpha.com/article/4866719-x-fab-silicon-foundries-se-xfabf-q4-2025-earnings-call-transcript
• X-FAB SiC/GaN technology page: https://www.xfab.com/technology/sic-gan ; Erfurt grant: https://www.xfab.com/news/details/article/grant-notification-presented-x-fab-develops-erfurt-site-into-a-center-for-microsystems-technology
• Capacity: https://www.linkedin.com/company/x-fab ; https://silicon-saxony.de/en/mitglieder/x-fab-semiconductor-foundries-gmbh-2/
• photonixFAB consortium: https://www.imec-int.com/en/press/photonixfab-consortium-now-open-first-prototyping ; https://optics.org/news/x-fab-leads-andeuro48m-silicon-photonics-effort
• Serenity post 2026-05-27: https://x.com/aleabitoreddit/status/2059537337324085541 ; coverage: https://www.bloomberg.com/news/articles/2026-05-27/popular-x-account-sparks-massive-rally-in-little-known-chipmaker ; https://www.investing.com/news/stock-market-news/xfab-silicon-foundries-stock-surges-after-social-media-post-93CH-4712788 ; https://www.lse.co.uk/news/chipmaker-x-fab-surges-in-retail-driven-rally-as-chip-frenzy-builds-i5aspyl867gqj4k.html
• Consensus: https://www.marketscreener.com/quote/stock/X-FAB-SILICON-FOUNDRIES-S-34541479/finances/ ; https://stockanalysis.com/quote/epa/XFAB/forecast/ ; https://www.investing.com/equities/x-fab-silicon-foundries-se-consensus-estimates ; https://meyka.com/blog/deutsche-bank-keeps-hold-on-xfabf-x-fab-silicon-lowers-pt-feb-2026-1002/
• Price/book: https://www.morningstar.com/stocks/xpar/xfab/quote ; https://finance.yahoo.com/quote/XFAB.PA/key-statistics/
• SiPh foundry peers: https://photoncap.net/p/the-silicon-photonics-foundry-layer (2026-10-01) ; Tower: https://towersemi.com/2026/08/04/08042026/ ; GF: https://www.trendforce.com/news/2026/05/07/news-globalfoundries-reportedly-sees-silicon-photonics-revenue-doubling-in-2026-passing-1b-by-2028/ ; https://www.marketbeat.com/instant-alerts/globalfoundries-q2-earnings-call-highlights-2026-08-05/
• Market sizes: https://www.mordorintelligence.com/industry-reports/silicon-photonics-market ; https://www.precedenceresearch.com/silicon-photonics-market ; https://www.marketgrowthreports.com/market-reports/silicon-photonics-wafer-foundry-market-100327 ; https://www.businessresearchinsights.com/market-reports/silicon-photonics-wafer-foundry-market-121027 ; https://www.mordorintelligence.com/industry-reports/silicon-carbide-market ; https://www.persistencemarketresearch.com/market-research/silicon-carbide-sic-wafer-market.asp ; SiC vendor rankings (low quality): https://www.reportprime.com/silicon-carbide-sic-power-semiconductor-r5388/company
• Chips Act 2.0: https://digital-strategy.ec.europa.eu/en/library/proposal-chips-act-20 ; https://aeneas-office.org/2026/06/03/european-commission-unveils-proposed-chips-act-2-0/ ; https://www.europarl.europa.eu/legislative-train/theme-a-new-plan-for-europe-s-sustainable-prosperity-and-competitiveness/file-chips-act-ii
• Newsletter (opinion): https://revoaiution.substack.com/p/the-x-fab-playbook-an-easy-to-read (2026-08-24)