Abivax to be Added to Nasdaq Biotechnology Index

Abivax (Nasdaq: ABVX) will be added to the Nasdaq Biotechnology Index (NBI), effective prior to market open on December 22, 2025.

Rhea-AI Summary

Abivax (Nasdaq: ABVX) will be added to the Nasdaq Biotechnology Index (NBI), effective prior to market open on December 22, 2025. The inclusion follows the company meeting NBI eligibility requirements such as minimum market capitalization, average daily trading volume and public company seasoning.

Company management tied the index inclusion to progress advancing obefazimod, citing successful Phase 3 ABTECT Induction trials for ulcerative colitis. The NBI is reviewed annually in December and uses a modified capitalization-weighted methodology.

Positive

• Index inclusion effective prior to market open on Dec 22, 2025
• Inclusion tied to progress in Phase 3 ABTECT Induction trials for ulcerative colitis
• Met NBI eligibility criteria including market capitalization, trading volume, and seasoning

Negative

• None.

Argus Dec 19 session

+1.17% close to close Open Argus

Details

News Market Reaction – ABVX

On Dec 19, the first trading day after this news, ABVX closed 1.17% above the previous close.

Data tracked by StockTitan Argus for the Dec 19 session.

Market Context

This announcement highlights Abivax’s upcoming addition to the Nasdaq Biotechnology Index, signaling...

Analysis

This announcement highlights Abivax’s upcoming addition to the Nasdaq Biotechnology Index, signaling that it meets criteria for market capitalization, trading volume, and listing history. The news follows recent positive Phase 3 ABTECT ulcerative colitis data, major conference acceptances, and disclosures of a cash runway into Q4 2027. Investors may watch how index inclusion interacts with ongoing clinical milestones and future financial updates to shape Abivax’s position within the biotechnology sector.

Key Figures

Index inclusion effective date: December 22, 2025 Announcement time: 10:05 pm CET

Index inclusion effective date

December 22, 2025

Date Abivax added to Nasdaq Biotechnology Index (NBI)

Announcement time

10:05 pm CET

Time of press release announcing NBI inclusion

Historical Context

5 past events · Latest: Dec 17

5 events

1. Dec 17

   Scientific conference data

   24h Move

   -0.1%

   ECCO 2026 acceptances for 22 obefazimod inflammatory bowel disease abstracts.

2. Dec 15

   Earnings and runway

   24h Move

   -6.1%

   Q3 2025 financials, strong cash position and runway into Q4 2027.

3. Nov 03

   Clinical PRO data

   24h Move

   -3.5%

   Phase 3 ABTECT PRO results showing improved quality of life vs placebo.

4. Oct 06

   Phase 3 topline data

   24h Move

   +3.3%

   UEG late-breaking pooled results with meaningful efficacy and good safety.

5. Sep 29

   Conference acceptance

   24h Move

   +1.9%

   Additional late-breaking ABTECT induction abstracts accepted for UEG 2025.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

nasdaq biotechnology index, phase 3, ulcerative colitis, industry classification benchmark, +1 more

5 terms

nasdaq biotechnology index financial

"it will be added to the Nasdaq Biotechnology Index (Nasdaq: NBI), effective..."

A stock index that tracks the performance of biotechnology companies listed on the NASDAQ stock exchange, combining many firms into a single measure of the sector’s movement. Think of it as a thermometer or basket that shows whether biotech stocks are generally rising or falling; investors use it to gauge sector health, compare individual holdings against the industry, and as the basis for funds that let you invest in the whole group at once.

phase 3 medical

"advancing obefazimod through the successful Phase 3 ABTECT Induction trials..."

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

ulcerative colitis medical

"ABTECT Induction trials for ulcerative colitis and reflects the increased..."

A long-term inflammatory disease that causes repeated sores and irritation in the large intestine, leading to symptoms such as abdominal pain, urgent diarrhea, and fatigue. For investors, it matters because the condition creates a steady need for effective treatments, influences the size of drug and medical-device markets, and makes clinical trial results, regulatory decisions and treatment approvals material to companies’ revenue prospects—like watching for fixes to a recurring leak in an important building system.

industry classification benchmark technical

"companies according to the Industry Classification Benchmark."

A standardized system that groups companies into industries and sectors based on their main business activities, like a library catalog that puts similar books together. It matters to investors because it enables fair comparisons between peers, guides portfolio construction and sector allocation, determines which stocks belong in industry indexes or ETFs, and helps track industry-level risks and performance trends.

modified capitalization-weighted methodology financial

"The NBI is evaluated annually in December and is calculated under a modified capitalization-weighted methodology."

A modified capitalization-weighted methodology is a way of building a stock index that starts with companies sized by market value but then adjusts those weights to avoid any one firm dominating the index or to reflect additional considerations like tradability or sector balance. For investors, it matters because the adjustments change exposure and risk compared with a pure market-cap index — think of it as giving big players somewhat less voting power at a meeting so the outcome better represents the whole room.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Abivax to be Added to Nasdaq Biotechnology Index

PARIS, France – December 18, 2025 – 10:05 pm CET – Abivax SA (Euronext Paris: FR0012333284 – ABVX / Nasdaq: ABVX) (“Abivax” or the “Company”), a clinical-stage biotechnology company focused on developing therapeutics that harness the body’s natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases, today announced that it will be added to the Nasdaq Biotechnology Index (Nasdaq: NBI), effective prior to market open on Monday, December 22, 2025.

Didier Blondel, Chief Financial Officer of Abivax commented: “Our inclusion in the Nasdaq Biotechnology Index marks a significant milestone for Abivax. It highlights the meaningful progress we’ve made as a company, particularly in advancing obefazimod through the successful Phase 3 ABTECT Induction trials for ulcerative colitis and reflects the increased visibility and perception of Abivax within the global biotechnology community.”

The NBI is designed to track the performance of a set of securities listed on The Nasdaq Stock Market^® that are classified as either biotechnology or pharmaceutical companies according to the Industry Classification Benchmark. Companies in the Nasdaq Biotechnology Index must meet eligibility requirements, including minimum market capitalization, average daily trading volume and seasoning as a public company, among other criteria. The NBI is evaluated annually in December and is calculated under a modified capitalization-weighted methodology.

For more information about the NBI, visit: https://indexes.nasdaqomx.com/Index/Overview/NBI

About Abivax

Abivax is a clinical-stage biotechnology company focused on developing therapeutics that harness the body’s natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases. Based in France and the United States, Abivax’s lead drug candidate, obefazimod (ABX464), is in Phase 3 clinical trials for the treatment of moderately to severely active ulcerative colitis.

Contact:	Media Contact:
Patrick Malloy SVP, Investor Relations Abivax SA patrick.malloy@abivax.com +1 847 987 4878	LifeSci Communications Karissa Cross, Ph.D. Account Supervisor kcross@lifescicomms.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

When will Abivax (ABVX) be added to the Nasdaq Biotechnology Index?

Abivax will be added to the Nasdaq Biotechnology Index effective prior to market open on December 22, 2025.

Why was Abivax (ABVX) included in the Nasdaq Biotechnology Index?

The company met NBI eligibility requirements and linked inclusion to progress in Phase 3 ABTECT Induction trials for ulcerative colitis.

What eligibility requirements does the Nasdaq Biotechnology Index use for ABVX?

The NBI requires minimum market capitalization, average daily trading volume, and public company seasoning, among other criteria.

What date reviews the Nasdaq Biotechnology Index membership each year?

The Nasdaq Biotechnology Index is evaluated annually in December.

Does Abivax mention which program supported the NBI inclusion?

Yes; the company referenced progress advancing obefazimod and successful Phase 3 ABTECT Induction trials.

Where can I find more information about the Nasdaq Biotechnology Index (NBI)?

More information about the NBI is available on the Nasdaq indexes website at the NBI overview page.