FOLD's Merger Arbitrage Play Hits 341st in Volume as $4.8B BioMarin Deal Nears Close

Market Snapshot

Amicus Therapeutics (FOLD) traded flat on December 23, 2025, with a 0.00% change in share price. Despite the lack of price movement, the stock saw a significant decline in trading volume, with a daily turnover of $0.25 billion, representing a 45.02% drop compared to the previous day. This marked FOLD as the 341st most actively traded stock in the market, indicating reduced institutional activity or a shift in investor focus following recent developments. The stock’s recent volatility and trading dynamics reflect its transformation into a merger-arbitrage scenario following the announced acquisition by BioMarin Pharmaceutical.

Key Drivers

The primary catalyst for Amicus Therapeutics’ stock activity remains the all-cash acquisition agreement with BioMarin, which values the company at $4.8 billion or $14.50 per share. This 33% premium over FOLD’s prior closing price has redefined the stock’s pricing dynamics, shifting investor focus from standalone financial performance to the probability and timing of the deal’s completion. The acquisition, expected to close in Q2 2026, has been unanimously approved by both boards and is structured to be accretive to BioMarin’s non-GAAP earnings within a year. The transaction, funded by BioMarin’s cash reserves and $3.7 billion in non-convertible debt, has removed financing-related risks, narrowing the spread between the current share price ($14.18) and the offer price.

A critical underpinning of the deal’s rationale lies in Amicus’ commercial assets. The company’s two marketed rare-disease therapies—Galafold (Fabry disease) and Pombiliti/Opfolda (Pompe disease)—generated $599 million in net revenue over the past four quarters. Recent third-quarter 2025 results highlighted a $169.1 million revenue figure, with GAAP net income of $17.3 million, marking a shift from prior cash-burning operations to profitability. These metrics, combined with gross margins in the mid-80% range, positioned Amicus as an attractive target for BioMarin, which seeks to expand its rare disease portfolio and leverage Amicus’ global commercial infrastructure.

The resolution of patent litigation for Galafold further solidified the acquisition’s strategic value. Amicus reached settlements with Aurobindo and Lupin, extending U.S. exclusivity for the drug until 2037. This intellectual property clarity reduces future revenue uncertainties for BioMarin, ensuring long-term stability for a therapy with peak sales potential exceeding $1 billion. The settlements also align with BioMarin’s expertise in enzyme replacement therapies, reinforcing the acquisition’s strategic fit.

Analyst sentiment has adjusted in response to the deal. TD Cowen downgraded FOLD to Hold, adjusting its price target to $14.50 to reflect the cash offer, while pre-acquisition coverage had suggested higher upside, with an average price target of $16.78. The downgrade underscores the limited upside for FOLD beyond the merger price, as the stock now trades as a probability-weighted claim on the $14.50 cash consideration. Additionally, Amicus’ pipeline, including U.S. rights to DMX-200 (a Phase 3 asset for FSGS), adds optionality for BioMarin, though its financial contribution remains speculative until post-closing development decisions are made.

Looking ahead, FOLD’s price trajectory will hinge on deal execution risks rather than operational performance. Key milestones include the shareholder vote, regulatory approvals, and potential antitrust scrutiny. The stock’s current $0.32 per share discount to the offer price reflects market expectations of a mid-2026 close, with minimal adjustments for competing bids or unexpected delays. As the acquisition nears completion, FOLD’s volatility will likely diminish, transitioning from biotech-driven swings to a narrow merger-arbitrage spread. Investors will closely monitor proxy filings, financing conditions, and regulatory updates to assess the deal’s path to closure.