Forte Biosciences ($FBRX) Stock Hub: argenx Acquisition Completed at $77 Cash

01 What the outcome was

Three scenarios were open while the offer ran. Each is set against what the documents ended up showing.

The path that was taken

The transaction closed cleanly and on the announced schedule: the offer expired as scheduled on August 26 without an extension, the minimum condition was met with a wide margin at approximately 87.13%, and the merger became effective the next day. The last regular close of $76.99 on August 26, one cent below the consideration, is what a spread looks like when the market treats completion as close to certain, and the market was right.

The paths that were not taken

The upside case required a formally disclosed superior proposal or an agreed increase in the consideration. Neither appeared at any point between the July 27 announcement and the closing, so $77.00 remained the contractual price throughout. The downside case was a delay or a termination: a failed minimum-tender condition, a regulatory obstacle or a contractual dispute. None occurred. The HSR waiting period expired on August 18 without a second request, and the nine demand letters recorded on August 21 produced no lawsuit that Forte was aware of as of that date.

What remains scientifically open

The Phase 2 celiac disease data and the alopecia areata Phase 1b data are still scientifically important, and they now sit inside argenx. They no longer have a price attached to them on any exchange, because the security that carried that price no longer exists. Anyone tracking FB102 from here follows argenx disclosures.

What Would Falsify This Reading

These conditions would change the interpretation of this acquired-company archive.

• The closing record is corrected or legally challenged. A primary disclosure reversing or materially qualifying the completed transaction would change this archive’s interpretation. Primary source.
• Cash rights differ from the documented terms. A material discrepancy between payment rights and the disclosed merger terms would require reassessing the transaction record; historical trading prices do not replace those rights. Primary source.
• Future FB102 results are misread as a listed FBRX catalyst. The program continues within argenx. New clinical evidence can change the acquired asset’s scientific interpretation, but does not recreate the former public security. Primary source.

Conditional checks, not predicted events or investment recommendations.

02 Core thesis

argenx paid to add FB102’s anti-CD122 biology and multi-indication potential to its immunology portfolio after Forte produced positive early data in celiac disease and vitiligo.

03 How the closing is documented

Three documents record the closing, and they agree with one another. The Form 8-K filed by Forte on August 27, 2026 at 4:15 p.m. Eastern carries Items 2.01, 3.01, 3.03, 5.01, 5.02 and 5.03. Amendment No. 3 to the Schedule TO, filed by Avena Merger Sub, argenx BV and argenx SE at 9:27 a.m. the same morning, reports the expiration and the tender result. The argenx SE press release of August 27 at 8:50 a.m. Eastern, filed as Exhibit (a)(5)(vi) to that amendment, announces the completion. The tender figure, 19,894,879 shares and approximately 87.13%, is identical in all three.

The July 26 merger filing requires more than 50% of outstanding shares to be validly tendered, plus satisfaction or waiver of the other offer conditions, including the Hart-Scott-Rodino waiting period. The outside date is November 30, 2026, and Forte may owe a $65 million termination fee in specified circumstances. The offer documents were filed on August 6, 2026: a Schedule TO by Avena Merger Sub and argenx, and a Schedule 14D-9 in which the Forte board unanimously recommends that holders tender their shares. The second-step merger would follow under Section 251(h) of the Delaware General Corporation Law, without a shareholder vote. Forte merger 8-K · Pre-commencement Schedule TO communication.

What happened between August 18 and August 27

What the closing documents say, item by item. The offer expired one minute after 11:59 p.m. Eastern on August 26 and was not extended. Computershare, depositary and paying agent, advised that 19,894,879 shares had been validly tendered and not validly withdrawn; together with the shares argenx and its affiliates already owned, that is approximately 87.13% of the shares then outstanding, comfortably above the threshold of one share more than 50%. All other conditions were satisfied or waived. Purchaser irrevocably accepted the tendered shares for payment and will pay for them promptly. The merger followed on August 27 under Section 251(h) of the DGCL, so no meeting and no vote of Forte shareholders took place.

Where the 87.13% comes from, and why it does not divide into the cover-page share count. The offer to purchase discloses that argenx already held 951,655 shares, approximately 4.48% of the outstanding stock at August 5, 2026, bought for $25.0 million in the April 2026 follow-on at $26.27 per share. Add those to the 19,894,879 tendered and the numerator is 20,846,534. Divide that by the 21,229,087 shares on the Form 10-Q cover page and the answer is 98.2%, not 87.13%, so the two figures are measured against different bases. The comparison is complicated because the minimum condition is defined against the shares outstanding immediately following the consummation of the offer, and the cover-page count excludes the 3,956,842 pre-funded warrants outstanding at June 30, 2026, which the company reports separately and which are exercisable at any time for nominal consideration. Merlintrader reconstruction, not a disclosed figure: an 87.13% result on a numerator of 20,846,534 implies a denominator of roughly 23.9 million shares, which sits between the 21.23 million of common stock and the 25.19 million that common stock plus all pre-funded warrants would give. The closing documents do not publish that denominator. This arithmetic does not establish which warrants were exercised before expiration or account for every intervening share change; the final 87.13% remains the percentage reported by the closing documents.

What holders of the other instruments receive. Each option with an exercise price below $77.00 was cancelled and converted into a lump-sum cash payment equal to the difference multiplied by the shares under the option, subject to withholding. Each option with an exercise price equal to or above $77.00 was cancelled with no payment. Each restricted stock unit was cancelled and converted into a cash payment of $77.00 per underlying share. Holders of pre-funded warrants outstanding at the offer acceptance time keep the right to receive $77.00 for each share issuable on exercise, without regard to the exercise limitations in the warrant agreement.

Who runs the company now. All eight directors in office immediately before the effective time — Paul A. Wagner, Steven Kornfeld, Scott Brun, Barbara K. Finck, Stephen K. Doberstein, Richard Vincent, Shiv Kapoor and David Gryska — ceased to be directors, and every officer ceased to hold office. The directors and officers of Avena Merger Sub, namely Arjen Lemmen, Karl Gubitz and Hemamalini (Malini) Moorthy, took their place, and the certificate of incorporation and the bylaws were amended and restated in full.

What remains to happen on the SEC side. The Form 25 filed by Nasdaq removes the shares from listing and from registration under Section 12(b). September 8 update: three Form 15-12G notices have been filed; filing and deregistration effectiveness remain distinct steps. Form 15 — SEC

The supplemental disclosure of August 21, and why nine letters arrived

Amendment No. 2 to the Schedule 14D-9 states that since the original filing of August 6 the company received nine demand letters from purported holders, each alleging that the Schedule 14D-9 omitted material information and demanding corrective disclosure. Forte states it believes the claims are without merit, that as of August 21 it was not aware of any lawsuit filed against the transaction, and that it specifically denies any additional disclosure was required. Supplemental disclosure does not by itself resolve the merits of any legal allegation.

The supplemental figures are the interesting part, because they show the valuation work behind the $77.00.

• The projections. Management prepared unaudited forecasts for fiscal years 2026 through 2045, with risk-based adjustments, approved by the board for Guggenheim Securities to rely on. They were not provided to argenx.
• The discounted cash flow. A discount rate range of 11.75 to 14.50 per cent, the mid-year convention, and a valuation date of June 30, 2026. Terminal value used a perpetual growth rate of negative 50 per cent, reflecting the assumed global loss of exclusivity for FB102 in 2043. Tax expense assumed a 25 per cent rate and roughly $153 million of cash savings from tax assets in fiscal 2032 through 2034.
• The share count used. 20.49 million basic shares at July 24, 2026, plus the dilutive impact of options, restricted stock units, pre-funded warrants and employee purchase plan rights under the treasury stock method.
• The premium checks. Guggenheim reviewed thirteen precedent clinical-stage biopharma transactions since 2025 with enterprise values above $1 billion. The 25th to 75th percentile of one-day unaffected premia, 42 to 79 per cent, applied to the unaffected price of $54.78, gives $77.79 to $98.06 per share. The same percentiles of premia to 52-week highs, 13 to 48 per cent, applied to the $59.70 high, give $67.46 to $88.36. The offer price of $77.00 sits at or just below the bottom of the first range and inside the second.
• The analyst targets. Five Wall Street price targets published before the unaffected date ranged from $54.00 to $75.00, against the $77.00 offer.
• The adviser fee. Guggenheim’s transaction fee is currently estimated at approximately $43 million payable on consummation, against $2.0 million that became payable on delivery of the opinion and is credited against it.

Read together, those figures describe a price negotiated at the low end of the precedent premium range on the unaffected price and above every published analyst target. Both statements are true at once, and which one carries more weight depends on whether the unaffected price or the sell-side view is treated as the fairer benchmark. That is a judgment, and the disclosure exists so shareholders can make it themselves.

04 Company Overview

Forte Biosciences is a clinical-stage biopharmaceutical company focused on autoimmune and autoimmune-related diseases. Its development story is centered on FB102, a proprietary anti-CD122 monoclonal antibody therapeutic candidate. The company is headquartered in Dallas, Texas and traded on Nasdaq under the symbol FBRX until August 27, 2026. Under the merger agreement signed on July 26 and announced on July 27, Forte became a wholly owned subsidiary of argenx on completion of the tender offer and the second-step merger.

For investors, the most important historical point is that Forte has already gone through a major reset. The company previously developed FB-401 for atopic dermatitis. In September 2021, Forte announced that FB-401 failed to meet the primary endpoint in a Phase 2 trial. That failure reshaped the company and makes execution history relevant when evaluating the current FB102 story.

The current Forte is therefore not the same clinical narrative that existed before FB102 became the lead asset. The company became more focused and more concentrated, allowing a single program to drive a sharp revaluation after positive data. argenx’s $2.2 billion agreement validates the strategic importance of that program, although it does not remove the clinical and commercial risks of FB102 development.

05 FB102 and the CD122 Thesis

FB102 is designed to target CD122, the beta subunit shared by IL-2 and IL-15 receptor signaling. Forte’s thesis is that this pathway sits upstream of disease-relevant immune activity across multiple autoimmune conditions. The company has described FB102 as a way to modulate pathogenic T-cell and NK-cell biology while attempting to avoid overly broad immune disruption.

The appeal of this approach is easy to understand. Celiac disease, vitiligo and alopecia areata are different clinical diseases, but each involves immune-mediated tissue damage. In celiac disease, gluten exposure triggers immune injury in the small intestine. In vitiligo, autoimmune activity contributes to melanocyte destruction and depigmentation. In alopecia areata, immune attack targets hair follicles. Forte is trying to connect these diseases through a common immunologic axis.

The scientific risk is also clear. A mechanism that looks coherent across diseases does not automatically translate into broad clinical success. Each indication has its own endpoint, patient population, placebo behavior, regulatory standard, competitive bar and commercial reality. FB102 must prove itself disease by disease.

06 Pipeline and Indication Map

07 Celiac Disease: The Central Scientific Validation Program

Celiac disease was the most important standalone FBRX catalyst before the acquisition agreement and remains a central part of FB102’s strategic value to argenx. Forte initiated a Phase 2 celiac disease study after reporting positive Phase 1b data in June 2025. Company updates in 2026 continued to point to a Phase 2 readout in the second half of 2026, and the July 27 acquisition announcement reiterated that timing.

The earlier Phase 1b celiac study enrolled 32 subjects randomized 3:1 to FB102 or placebo. Subjects received four doses of FB102 at 10 mg/kg and underwent a 16-day gluten challenge. The study assessed safety and tolerability, morphologic and inflammatory endpoints, and gluten-challenge-induced symptoms.

The key data were encouraging. Forte reported a statistically significant benefit on the composite histological VCIEL endpoint, with placebo subjects showing a mean VCIEL change from baseline of -1.849 compared with 0.079 for FB102-treated subjects, producing a p-value of 0.0099. The company also reported that intraepithelial lymphocyte density increased by 13.3 in placebo subjects but declined by 1.5 in FB102-treated subjects, with a p-value of 0.0035.

Symptom data also leaned in the right direction. Forte reported that gluten-challenge-induced gastrointestinal symptom events occurred at 4.0 events per subject in the FB102 arm versus 6.9 events per subject in the placebo arm, representing a 42% benefit. The trial had no dropouts, and treatment-emergent adverse events were primarily Grade 1, with no Grade 3 or higher serious adverse events reported in the FB102 arm.

The Phase 2 trial is the real test because celiac disease is not an easy development category. Gluten-free diet remains the foundation of treatment, but accidental exposure and persistent symptoms create a real unmet-need narrative. A drug that can protect intestinal histology, reduce immune activation and improve symptoms could attract meaningful attention. But the clinical and regulatory bar is not trivial. Endpoints must be interpretable, effects must be clinically meaningful, and safety must be acceptable for a chronic disease population.

08 Vitiligo: The July 2026 Data That Preceded the Acquisition

The vitiligo update added a second clinical indication to the acquisition rationale. On July 9, 2026, Forte announced positive results from the FB102 double-blind, placebo-controlled Phase 1b study in non-segmental vitiligo. The study enrolled 43 subjects randomized 3:1, with 32 receiving FB102 and 11 receiving placebo.

The primary endpoint was mean percent improvement from baseline in Facial Vitiligo Area Scoring Index, or FVASI, assessed by central review. In the protocol-defined efficacy-evaluable population, which included 32 FB102-treated subjects and 10 placebo subjects, FB102 achieved a 29.6% mean FVASI improvement from baseline at Week 24 versus 7.9% for placebo. That produced a placebo-adjusted FB102 benefit of 21.7% and a p-value of 0.020.

The intent-to-treat analysis looked even more separated because placebo worsened. Forte reported that in the ITT population, FB102 improved by 29.6% from baseline while placebo deteriorated by 16.2%, producing a placebo-adjusted benefit of 45.8% and a p-value of 0.005. The difference between the ITT and protocol-defined analyses is important because a single placebo subject with facial hair and substantial progression was excluded from the protocol-defined efficacy-evaluable population.

The subgroup with baseline FVASI of at least 0.75 was especially notable. Forte reported that in subjects with greater disease involvement, FB102 achieved a 43.2% mean FVASI improvement from baseline at Week 24 compared with 0.5% for placebo, producing a placebo-adjusted benefit of 42.7% and a p-value of 0.006. In that subgroup, 10 of 17 FB102-treated subjects achieved FVASI50, or 58.8%, and 4 of 17 achieved FVASI75, or 23.5%. No placebo subject in that subgroup achieved FVASI50 or FVASI75.

Durability after the dosing period is another part of the signal. Forte said response to FB102 was observed early, with statistically significant improvement by Day 64, and continued through Week 24 after completion of the 12-week treatment period. The company reported that subjects continued improving between Week 12 and Week 24, with an additional eight percentage-point mean FVASI improvement overall and a fourteen percentage-point improvement in subjects with baseline FVASI of at least 0.75.

The safety description was also supportive for an early trial. Forte reported a favorable safety profile compared with placebo and said adverse events were mild to moderate. That language is particularly important in vitiligo because any systemic immunomodulatory therapy must clear a high tolerability bar, especially when an approved topical therapy already exists.

The competitive context cannot be ignored. The FDA approved Opzelura, ruxolitinib cream, for non-segmental vitiligo in adult and pediatric patients 12 years and older in 2022. That means any future FB102 vitiligo program under argenx must eventually show why a systemic anti-CD122 antibody deserves a place in a market where topical JAK inhibition is already available. Possible differentiation could come from patient selection, durability, response depth, systemic disease biology or specific populations, but those points remain unproven until larger trials are designed and reported.

09 Alopecia Areata: Logical Extension, Harder Competitive Bar

Alopecia areata fits Forte’s immune-biology thesis because the disease involves immune-mediated attack on hair follicles. Forte has guided for a Phase 1b alopecia areata readout in 2026. If positive, this could provide a third clinical signal for FB102 and strengthen the argument that CD122 modulation has repeatable relevance across autoimmune dermatology and gastrointestinal disease.

However, alopecia areata is not an empty field. The therapeutic landscape has already changed significantly with approved JAK inhibitor options. This matters because investors should not treat every positive early autoimmune signal as commercially equal. A future FB102 alopecia signal would need to be viewed against existing therapies, safety expectations, speed of response, durability and patient-selection strategy.

For this file, alopecia areata was scientific optionality inside the transaction rationale rather than a public-market valuation pillar, and the $77.00 consideration settled the equity outcome. Celiac disease, vitiligo and alopecia together explain why argenx paid what it paid.

10 Financial Position, Cash Runway and Burn

The figures in this section describe Forte as it stood at June 30, 2026, the last balance-sheet date it reported as an independent public company. argenx funded the $77-per-share purchase entirely from its own cash on hand, approximately $2.2 billion in all, and Forte’s clinical spending is now part of argenx. The cash, burn and runway numbers below are kept because they explain what argenx acquired and what it no longer has to fund from an equity market, not because they still describe a company that has to raise money on its own.

Forte reported $49.6 million in cash and cash equivalents plus $148.8 million in short-term investments at June 30, 2026, which the company presents together as $198.5 million. Current assets were $203.1 million, total assets were $205.7 million, current liabilities were $20.3 million, total liabilities were $21.9 million and shareholders’ equity was $183.8 million. The company reported no product revenue, which is normal for a clinical-stage biotech but important for risk framing.

Operating expenses stayed high through the second quarter. Research and development expense was $22.2 million in Q2 2026 and $42.5 million for the first half, against $20.3 million in Q1. The company attributes the level of spending to the Phase 2 celiac disease trial and the Phase 1b trials in vitiligo and alopecia areata, plus preclinical and personnel costs. General and administrative expense was $2.3 million in Q2 and $4.2 million for the first half. The net loss was $23.3 million in Q2 and $45.5 million for the first half, or $0.97 and $2.18 per share. Operating cash use was $41.5 million over the six months.

The April 2026 public offering materially changed the capital picture. Forte priced 5,709,936 common shares at $26.27 per share, with an underwriters’ option for up to 856,490 additional shares. The 424B5 filing shows total public offering proceeds of approximately $172.5 million with the over-allotment option, underwriting discounts and commissions of approximately $10.35 million, and proceeds before expenses to Forte of approximately $162.15 million.

The Q2 10-Q replaces the earlier editorial bridge with a reported figure: $198.5 million of cash and short-term investments at June 30, 2026, after the April proceeds and after $41.5 million of operating cash use in the first half. Forte therefore entered the tender period with a funded balance sheet, which was relevant to the pre-closing standalone scenario and is now historical.

Positive financial read-through

The April raise reduced immediate financing pressure and allowed Forte to negotiate from a stronger balance-sheet position. The completed acquisition had no financing condition and was funded from argenx’s cash on hand.

Remaining financial risk

Before the acquisition, Forte was pre-commercial and a delay or termination would have meant that larger trials, regulatory work and indication expansion would again make burn rate and future dilution central to standalone valuation; that transaction scenario did not occur.

The reported R&D line and the historical chart exclude related-party research and development: a separate $0.150M in Q2 and $0.300M in H1 2026. Including that line gives $22.336M and $42.806M respectively. 10-Q.

11 Dilution, Share Count and Capital Structure

Dilution is central to the $FBRX story. Forte reported 13.9 million common shares and 4.0 million pre-funded warrants outstanding at March 31, 2026. After the April 2026 offering the count rose to 20,482,400 common shares at June 30, 2026, and to 21,229,087 as of August 7, 2026 on the cover of the Q2 10-Q. Approximately 4.43 million securities were excluded from the diluted loss per share calculation for the first half because they were anti-dilutive.

The April offering was strategically useful because it strengthened the balance sheet before major readouts. But it also expanded the share count. That trade-off is common in biotech: companies often raise when data or expectations allow them to finance at better levels, and investors then have to decide whether the added runway offsets the dilution.

The fully diluted picture is more complex than the basic share count. Before the acquisition, Forte had pre-funded warrants, options, restricted stock units and shares reserved under equity incentive plans. The company also used shelf registration capacity as part of its then-standalone funding structure. Shelf capacity does not mean an immediate raise, but it is part of the normal funding toolkit for a clinical-stage biotech.

The merger settled all of it. Every outstanding common share was purchased in the offer or converted into the right to receive $77.00 in cash, options in the money were cashed out at the spread, options at or above the price were cancelled for nothing, restricted stock units were cashed out at $77.00 per underlying share, and pre-funded warrant holders kept the right to $77.00 for each share issuable on exercise. Standalone dilution stopped being a question on August 27, 2026.

12 Management and Execution Profile

Until the effective time on August 27, 2026, Forte was led by Paul Wagner, Ph.D., as CEO and chairman. The leadership team also includes finance, operations and clinical-development executives with biotechnology and drug-development backgrounds. For a company at this stage, the key execution questions are not branding or commercial scale; they are trial design, enrollment, regulatory alignment, manufacturing readiness and capital allocation.

Execution history deserves a balanced reading. Forte’s prior FB-401 program failed its Phase 2 atopic dermatitis endpoint in 2021, which is a legitimate reminder that early promise can fail in controlled trials. But FB102 is a different asset and a different mechanism. The current evidence should therefore be judged on FB102’s own clinical data, while still remembering that the company has already experienced a major clinical reset.

The last execution test this management team faced was the transaction itself, and it was passed: signed on July 26, offer commenced August 6, antitrust cleared August 18, expiration met on August 26 with roughly 87% tendered or already owned by argenx, merger effective August 27. All eight directors and every officer left office at the effective time. The Phase 2 celiac readout remains a major scientific milestone for the second half of 2026, and it is now argenx’s to deliver.

13 Red Flags and Monitoring Checklist