Tower Semiconductor — Forward Catalyst Calendar

This file enumerates the discrete forward events that will materially update the TSEM thesis between 2026-04-29 and the end-2028 horizon (the window over which the publicly-disclosed FY 2028 financial-model target — $2.84B revenue, 39-40% GM, 31.7% Op margin per Tower Q4 2025 release ✓, TipRanks ✓ — must materialize). Each catalyst is mapped to (a) its date or expected window, (b) its primary thesis significance (which bull / bear pillar or risk it tests), (c) the disclosure path that would surface the result, and (d) a magnitude flag (H = high / M = medium / L = low) calibrated to the share-price reaction range typical for a similar-magnitude event in Tower’s recent history.

Tower files as a Foreign Private Issuer (FPI) under SEC rules — the disclosure cadence is materially less rich than for US-domestic issuers. The principal annual filing is the 20-F (annual report); interim disclosures are made via 6-K (quarterly earnings + select material-event disclosures). There is no 10-Q equivalent, no DEF 14A proxy, and no Form 4 insider-transaction filing system that mirrors the US-domestic regime — though HFIAA Section 16 newly applies to FPIs as of 2026-03-18 (SEC FPI rule release ✓), which adds incremental insider-disclosure requirements that are still ramping into Tower’s reporting practice. The reduced disclosure cadence relative to US peers is itself a thesis-relevant fact: catalyst surprises are concentrated at the four 6-K quarterly events plus the annual 20-F.

Used together with the risk register and the bull case / bear case, this catalyst calendar is the analytical scaffolding for monitoring the position thesis quarter-by-quarter.

Near-term (next 6 months: May 2026 - October 2026)

Date / window	Event	Magnitude	Thesis significance	Disclosure path
May 13 2026	Q1 2026 6-K earnings release + conference call (per Tower IR forward-calendar ⚠ inferred-typical-cadence; primary IR confirmation pending)	H	First post-FY 2025 6-K print. Tests bull case Pillars 1-3 (PH18 SiPh trajectory, RF Infrastructure mix, Agrate operating-leverage flow-through) and bear case Pillars 1, 3 (RF Mobile cyclicality, AI-photonics revenue contribution). Specifically tests: did SiPh revenue grow >50% YoY in Q1 2026 (Pillar 1.1 confirm)? Did GM hold >24% sequentially (Pillar 2.2 confirm)? Did RF Mobile mix stay above 22% of revenue (Pillar 1.1 bear falsify)?	SEC EDGAR 6-K + Tower IR press release; live call + transcript via Investing.com, Yahoo Finance, StockTitan.
April-May 2026	FY 2025 20-F filing (annual report on Form 20-F; per Tower’s typical cadence, prior-year 20-F filed 2025-04-30 acc. 0001178913-25-001537 ✓; FY 2025 expected late-April or early-May 2026)	H	Critical disclosure window: (a) full-year audited segment revenue including SiPh + SiGe disaggregation, (b) named-customer concentration disclosures (Item 4 / Item 5 of 20-F format), (c) refreshed risk-factor language (Israel-conflict, customer-concentration, Chinese mature-node ASP pressure), (d) management’s discussion of $920M capex envelope progress + customer-prepayment quantum, (e) Tower-Intel Fab 11X capacity-deployment status. The risk-factor diff alone is a high-density signal.	SEC EDGAR 20-F filing; Tower IR press release. Risk-factor diff tracking via risk_factor_diff.json ◐.
August 2026 (target)	Q2 2026 6-K earnings release + conference call	H	Mid-year FY 2026 print. Tests trajectory toward the management-implied SiPh ramp consistent with FY 2028 model ($2.84B at +22% CAGR from FY 2025 → ~$1.9B FY 2026). First quarter to potentially reflect initial wafers from Tower-Intel Fab 11X (per the $300M equipment-investment ramp targeting initial wafers H1 2026).	SEC EDGAR 6-K + Tower IR press release; live call + transcript.
June-September 2026	Tower-LWLG PH18 development-agreement engineering tapeout milestones (multiple tapeouts during 2026 per LWLG-Tower joint announcement ✓)	H	The agreement specifies “multiple engineering tapeouts during 2026” targeting 110 GHz+ bandwidth for 200G/400G per-lane modulator architectures. First-tapeout success or failure is the single most-significant photonics-customer-validation event on the calendar. Tests bull case Pillar 1.2 (LWLG integration) + LWLG bull case Pillar 1 (foundry-licensing playbook).	Joint Tower + LWLG press release; LWLG 10-Q + 10-K disclosures (LWLG is US-domestic issuer, richer disclosure cadence); industry-conference disclosure (potential ECOC 2026 or industry-show venue).
September 21-25 2026	ECOC 2026 (Brussels — European Conference on Optical Communication) ⚠ inferred dates	M	Tower historical disclosure venue for PH18 process updates + customer co-presentations. Likely venue for any LWLG-PH18 first-tapeout disclosure if the timeline tracks. Tests bull case Pillar 1 (PH18 customer-roster expansion) + risks X1 (GFS Fotonix competitive comparison at industry-conference layer).	ECOC technical program; Tower technical presentations; partner co-presentations (Coherent, LWLG, hyperscaler-tier customers).
September 2026	CIOE 2026 (Shenzhen, target Sept 2026) ⚠ inferred dates	L	China Optoelectronics Exposition. Tower has limited direct presence but module-OEM partner displays of PH18-based transceivers signal volume-ramp visibility for the Asian module-OEM market.	CIOE program; module-OEM partner press releases (Innolight, Eoptolink, Hisense Broadband).
October-November 2026 (target)	Q3 2026 6-K earnings release + conference call	H	Three-quarter view of FY 2026 trajectory. Critical for the $920M capacity envelope December 2026 milestone tracking. Tests bull case Pillar 3.3 (capacity multiplier > 5× by Dec 2026) — Tower must show clear capacity-ramp evidence by Q3 2026 to credibly hit the Dec 2026 target.	SEC EDGAR 6-K + Tower IR press release.

Medium-term (6-18 months: November 2026 - October 2027)

Date / window	Event	Magnitude	Thesis significance	Disclosure path
December 2026	$920M SiPho/SiGe capex envelope — December 2026 wafer-starts capacity multiplier milestone (>5× Q4 2025 actual, with >70% reserved through 2028 backed by customer prepayments per Tower Q4 2025 release ✓)	H	The single most-testable execution milestone in the FY 2028 model trajectory. If hit on time: Pillar 3.3 confirmed, FY 2028 model timing remains intact, multiple expansion sustained. If slipped beyond Q1 2027: Pillar 3.3 weakens, the FY 2028 model timing pushes 12-18 months, multiple compresses 2-3 turns.	Q4 2026 6-K release (typically Feb 2027) + Tower IR commentary; capex disclosure in FY 2026 20-F.
H1 2026 → H2 2026 (production)	Tower-Intel Fab 11X capacity ramp from $300M equipment investment — initial wafers H1 2026, productionized H2 2026 (per Tower-Intel arrangement disclosure ⚠ inferred-from-aggregator; primary-source verification queued)	H	Tower-Intel Fab 11X is the New Mexico facility purchased from Intel in 2024. The $300M equipment-investment program adds 300mm specialty-foundry capacity for Tower’s RF Infrastructure + power-management product lines. Tests bull case Pillar 3 (capacity expansion), risks T2 (capacity-ramp execution).	Tower 6-K capex disclosures; Fab 11X commissioning announcements; segment-revenue contribution disclosed in subsequent 6-Ks.
December 2024 + ongoing 2025-2026	Tower-ST Agrate full-capacity ramp — next 65nm BCD productized December 23 2024 (Tower release ✓); subsequent platforms 2025-2026	M	Tower-ST Agrate 300mm Italy joint venture has been absorbing operational cost since Q4 2024 ahead of meaningful revenue. As subsequent platforms productize through 2025-2026, the cost drag flips to operating leverage. Tests bull case Pillar 2.2 (Agrate operating-leverage flow-through). The +640 bps GM expansion across 2025 (20.4% Q1 → 26.8% Q4) is the load-bearing data point. Continued GM expansion in 2026-2027 confirms the JV economics.	Quarterly 6-K GM trajectory; ST Microelectronics Q4 commentary (ST is the JV partner; ST’s quarterly disclosures provide independent triangulation).
2026-2027	First CPO Foundry Program customer disclosure (per Tower CPO Foundry Program announcement Nov 12 2025 ✓); first customer disclosure expected 2026-2027 (analyst expectation ⚠ inferred from industry-typical 12-18 month foundry-program-to-first-customer cycle)	H	The CPO Foundry Program announcement (Nov 12 2025) opened a new product line: PH18 + EIC (Electronic Integrated Circuit) optical platforms with CPO-design-rule support. First CPO customer announcement (likely an AI-cluster system vendor or hyperscaler-tier module OEM) would confirm Tower’s positioning at the architectural-shift layer where co-packaged optics replaces pluggable transceivers. Tests bull case Pillar 1 (PH18 customer-roster expansion) + risks T4-equivalent (CPO architectural shift positioning).	Tower joint press release with the CPO customer; OFC 2027 / OFC 2028 disclosure venues (premier industry venue for CPO architectural disclosure).
2026 (full year)	Additional silicon-photonics customer announcements beyond Coherent + LWLG	H	The two publicly-disclosed PH18 photonics-customer markers as of 2026-04-29 are: (a) Coherent (OFC 2026 400G/lane SiPh demonstration ⚠ specific Tower-Coherent-PH18 attribution requires primary-source verification — Tower-Coherent partnership is a 2026 OFC marker), and (b) Lightwave Logic (March 11 2026 development agreement ✓). Each subsequent named-customer announcement (Marvell, Broadcom, NVIDIA, Cisco, Lumentum, Innolight, Eoptolink, Hisense Broadband) materially advances the bull case. Probability of at least one new named photonics customer in 2026 H2 is high ⚠ analyst inference based on Tower’s established disclosure cadence at industry conferences.	Tower joint press release; OFC 2026 (March 2026 — already passed), ECOC 2026 (Sept 2026), OFC 2027 (March 2027) industry venues.
March 2026 (already passed)	OFC 2026 (San Diego, March 2026) — Tower-Coherent partnership demonstration	M (retrospective)	Already-passed catalyst. Tower-Coherent partnership at OFC 2026 demonstrated 400G/lane SiPh ⚠ specific Coherent-Tower-PH18 attribution pending primary-source verification. The retrospective signal: did the demonstration translate to subsequent customer-pipeline disclosure or design-win activity? Tracking opportunity is in the FY 2025 20-F (Apr-May 2026 filing) and Q1-Q2 2026 6-Ks.	OFC 2026 technical program; Tower IR commentary on Q1 2026 6-K.
Late-2026 to early-2027	Possible US CHIPS Act funding announcement for Tower-Intel Fab 11X New Mexico facility ⚠ analyst inference; no Tower-specific CHIPS Act award has been disclosed as of 2026-04-29	H if granted, L if not	The Tower-Intel Fab 11X facility (Albuquerque, NM) is a US-domestic 200mm/300mm specialty-foundry asset that fits CHIPS Act eligibility criteria (US-domestic-fab capacity expansion + specialty-process diversification). Tower has not publicly committed to a CHIPS Act application; an award would materially de-risk the Fab 11X capex envelope. Probability ⚠ inferred at 25-40% based on (a) eligibility criteria fit, (b) Tower’s documented Fab 11X investment program, (c) the political-economy framing of US-Israeli specialty-foundry partnerships under post-2026 administration.	NIST + Department of Commerce CHIPS Act award announcements; Tower IR press release.
April-May 2027 (target)	FY 2026 20-F filing	H	Full-year FY 2026 audited segment revenue + risk-factor refresh + capex-deployment update. Tests bull case Pillar 1 (FY 2026 SiPh segment revenue), bear case Pillar 1 (RF Mobile + specialty-cycle trajectory).	SEC EDGAR 20-F filing.
March 2027	OFC 2027 (San Diego, March 2027) ⚠ inferred date	H	Premier industry venue. Hyperscaler module-spec disclosures (3.2T architecture); CPO-vs-pluggable architectural inflection visibility; Tower CPO Foundry Program first-customer disclosure window. Tests bull case Pillar 1 entirely + risks X1, X2, X3 (GFS Fotonix, Intel SiPh, TSMC SiPh competitive landscape).	OFC 2027 technical program + Tower press releases + customer co-presentations.

Long-term (18+ months: November 2027 - end-2028)

Date / window	Event	Magnitude	Thesis significance	Disclosure path
April-May 2028 (target)	FY 2027 20-F filing	H	Critical FY 2028 model trajectory verification: FY 2027 revenue must inflect to ~$2.4B (vs FY 2025 $1.57B) for the FY 2028 $2.84B target to remain plausible at the +22% CAGR pace. SiPh segment FY 2027 revenue should print at $500-800M (per [user-prompt analyst inference ⚠]) for the bull case to remain on track.	SEC EDGAR 20-F filing.
2027 H2 → 2028	Silicon-photonics revenue scaling toward $400-500M FY 2027+ implied by FY 2028 model	H	The FY 2028 $2.84B revenue target with SiPh estimated at 25-35% of mix (bull case synthesis) implies SiPh revenue at $700M-$1B FY 2028 — requiring FY 2027 SiPh at $500-800M. Each quarterly 6-K through 2027-2028 tracks against this trajectory.	Quarterly 6-K segment-revenue prints.
End-2028 (Q4 2028)	FY 2028 financial-model target deadline — $2.84B revenue, ~39-40% GM, 31.7% Op margin (per Tower Q4 2025 release ✓, TipRanks ✓)	H	The single highest-impact thesis-defining moment. If Tower exits Q4 2028 at $700M+ quarterly run-rate (= $2.84B annualized) with 39-40% GM and 31.7% Op margin, the bull case is structurally confirmed and the equity supports a multiple-expansion narrative toward valuation ranges bull-case prices. If revenue tracks $2.3-2.5B (15-20% miss), bull case is partially delivered but multiple-expansion math is reduced. If revenue tracks <$2.0B, bear-case multiple-compression dominates and equity drifts toward $50-100/share specialty-foundry comp range.	FY 2028 20-F + final quarterly 6-K + earnings call.
2026-2028 (cumulative)	RF Infrastructure margin trajectory — segment exits 2025 at 32% of revenue; bull case implies sustained mix expansion + ASP improvement	M	RF Infrastructure mix at 32% Q4 2025 vs 24% RF Mobile mix Q4 2025 — the segment shift drives blended GM expansion independent of SiPh. Each quarterly print tracks the mix-shift trajectory.	Quarterly 6-K segment-mix disclosures.
2027-2028	Subsequent Tower-ST Agrate platform productization (post-65nm BCD)	M	Each subsequent Agrate platform (next-generation power, RF, image-sensor processes) compounds the operating-leverage flow-through. Tests bull case Pillar 2.2 across multi-year window.	ST Microelectronics quarterly disclosures + Tower 6-K commentary.
2028 (full year)	Possible US CHIPS Act funding milestone disclosures (if award granted in 2026-2027)	L-M	If a CHIPS Act award materialized, milestone-tracking disclosures (capex deployment, job creation, fab construction) would appear in 20-F MD&A. Clawback risk if milestones slip.	NIST + Department of Commerce annual reports + Tower 20-F.

Risk-mapping summary table

Cross-references each catalyst window to the most-tested bull / bear pillars and the risks IDs:

Catalyst window	Bull pillars tested	Bear pillars tested	Risk IDs tested
Q1 2026 6-K (May 13 2026)	1, 2, 3	1, 3	C1, M1, M2, X1
FY 2025 20-F (April-May 2026)	All 3	All 3	All categories — risk-factor diff is comprehensive
Q2 2026 6-K (Aug 2026)	1, 3	1, 3	C1, T1, M1
LWLG-PH18 first tapeout (mid-2026)	1.2	3.3	T1, T3, X1
ECOC 2026 (Sept 2026)	1, 3	3	T1, X1, X2
Q3 2026 6-K (Oct-Nov 2026)	3.3	1	M1, T2
Dec 2026 capacity milestone	3.3	3.3	T2, K1, K2
Tower-Intel Fab 11X H2 2026 production	3	—	T2, K1
Tower-ST Agrate continuing ramp	2.2	—	T2
First CPO Foundry customer (2026-2027)	1	3.3	X1, T3
Additional SiPh customer announcements (2026 H2)	1	3.3	C1, X1
US CHIPS Act award (late-2026 — early-2027, if granted)	3	1	K1, K2, R-equivalent
FY 2026 20-F (April-May 2027)	All 3	All 3	All categories
OFC 2027 (March 2027)	1	3	T3, X1, X2, X3
FY 2027 20-F (April-May 2028)	3	3	All categories — final pre-target year
End-2028 FY 2028 target	All 3	All 3	All categories

Aggregate-thesis re-rating windows

The catalyst calendar identifies four discrete windows when the TSEM thesis can mechanically re-rate to the bull / base / bear case end-points described in bull case and bear case, and modeled in valuation ranges:

May-September 2026 (Q1 + Q2 6-Ks + FY 2025 20-F + LWLG-PH18 first tapeout + ECOC 2026): the highest-density catalyst window of the next 24 months. Six discrete data points (Q1 6-K, FY 2025 20-F, mid-2026 LWLG tapeout, Q2 6-K, additional SiPh customer announcements, ECOC) all land in a five-month window. Each one positively-skewing materially extends the multiple-expansion runway; conversely, a stack of two or more disappointing events would prompt immediate -10 to -20% drawdown risk.
December 2026 capacity milestone window: the single hardest binary execution test. Tower committed to >5× Q4 2025 SiPh/SiGe wafer starts by Dec 2026 with >70% reserved through 2028 backed by customer prepayments. Pass-or-fail visibility is concentrated in the Q4 2026 6-K (typically Feb 2027) and the FY 2026 20-F (typically Apr-May 2027).
Q3-Q4 2027 / FY 2027 20-F (April-May 2028): midpoint of the FY 2028 trajectory. SiPh revenue should be tracking $500-800M in FY 2027. Anything materially below is a Pillar 1 / Pillar 3 bull-case break.
End-2028 Q4 print + FY 2028 20-F (Apr-May 2029): the structural target moment. The FY 2028 model is met or missed.

If all four windows confirm the bull thesis, valuation ranges bull-case price targets ($250-300/share) become reachable. If any one window confirms the bear thesis, the valuation drifts toward the base/bear range.

Catalyst-calendar uncertainty notes

Several catalysts above carry analyst-estimate dating that should be flagged:

Q1 2026 earnings (May 13 2026): ⚠ inferred-typical-cadence; primary IR confirmation pending
FY 2025 20-F filing (April-May 2026): ⚠ pattern-based on prior 20-F filing 2025-04-30
Q2/Q3 2026 6-Ks: ⚠ pattern-based on quarterly cadence; specific dates pending
LWLG-PH18 first tapeout disclosure: ⚠ “multiple tapeouts during 2026” is the disclosed window; specific mid-year timing is analyst inference
First CPO Foundry customer: ⚠ “2026-2027” is analyst expectation; Tower has not committed to a specific window
US CHIPS Act award: ⚠ probability-flagged at 25-40%; no Tower-specific application has been publicly disclosed
Tower-Intel Fab 11X production timing: ⚠ “initial wafers H1 2026, productionized H2 2026” is per user-prompt aggregator-derived; primary Tower 6-K extraction queued
OFC 2027 / ECOC 2026 dates: ⚠ inferred from typical industry-conference annual cadence

Confirmed dates are sourced from Tower IR press releases and SEC filings; estimated dates are the analyst’s pattern-projection and should be re-verified as primary disclosures emerge.

What this calendar deliberately does not include

The research-prompt direction explicitly noted that catalyst entries should be primary-sourced where possible. The following types of catalysts have been deliberately not added or have been flagged with ⚠:

Sell-side analyst rating-change events: not catalysts in the primary-source sense; rating changes are aggregator-tracked and frequently lagged
Mubadala-equivalent overhang events: Tower has no controlling-shareholder selldown overhang — it is a fully-distributed-float listed equity post-Intel-deal-collapse
M&A optionality events: while Tower’s strategic posture allows for future M&A (Tower as buyer; Tower as target — note the August 2023 Intel deal at $5.4B / $53/sh ✓), the probability of a near-term repeat M&A event is low and not modeled here
Specific earnings-revision events: implicit in each 6-K but not separately catalogued