ABVX

The most significant contributor to the stock's rise was renewed speculation about a potential takeover by Eli Lilly. Reports from French publication La Lettre indicated that Lilly representatives had met with France’s Treasury officials earlier in December to assess the regulatory framework for a possible acquisition. Although no confirmed bid has been made, the market often reacts enthusiastically to such takeover rumors, especially when it involves a large pharmaceutical company like Eli Lilly. The mere prospect of such a deal can inflate the stock price as investors anticipate a favorable outcome.

Another catalyst was Abivax's addition to the Nasdaq Biotechnology Index (NBI), effective before the market opened on December 22, 2025. Index inclusion can lead to increased visibility and potential buying interest from funds tracking the index, although this effect is often short-lived. However, Abivax's strategic positioning and the prestige of being part of this index likely bolstered investor confidence in the company's future prospects.