FOLD’s Merger Arbitrage Drama Fizzles as $440M Volume Plunges to 217th Rank

Market Snapshot

Amicus Therapeutics (FOLD) edged up 0.21% on December 22, 2025, with a trading volume of $440 million, a sharp 83.43% decline from the previous day’s activity. The stock ranked 217th in trading volume for the session, reflecting muted post-announcement liquidity despite the ongoing merger arbitrage dynamics. The price action followed a dramatic 30% surge on December 19 after BioMarin’s $14.50-per-share cash acquisition offer was announced, pushing FOLD near its 52-week high of $14.36.

Key Drivers

The acquisition of Amicus Therapeutics by BioMarin Pharmaceutical Inc. for $4.8 billion in cash emerged as the central catalyst for FOLD’s recent volatility. The deal, offering a 33% premium to Amicus’s pre-announcement closing price, values the company at $14.50 per share and is expected to close in Q2 2026. BioMarin’s rationale centered on acquiring two rare-disease therapies—Galafold for Fabry disease and Pombiliti/Opfolda for Pompe disease—that generated $599 million in combined revenue over the past four quarters. The transaction also secures Galafold’s U.S. exclusivity through 2037 via patent settlements with Aurobindo and Lupin, addressing a key risk for BioMarin.

Analyst sentiment shifted following the deal’s announcement, with TD Cowen downgrading Amicus from Buy to Hold and aligning its price target with the $14.50 cash offer. The firm cited the fixed valuation as limiting upside potential, even as it acknowledged Amicus’s strong gross profit margins (nearly 90%) and projected profitability for 2025. Meanwhile, BioMarin’s stock initially dipped 3% premarket, reflecting market skepticism about the deal’s accretion to earnings, though it later rebounded amid optimism about revenue diversification and long-term growth in the rare disease sector.

Amicus’s recent financial performance further bolstered its appeal as an acquisition target. The company reported third-quarter 2025 earnings with non-GAAP EPS of $0.06—surpassing estimates—and revenue of $169.1 million, outpacing forecasts by $3.35 million. This growth was driven by robust sales of Galafold and Pombiliti/Opfolda, alongside strategic market expansion. Analysts highlighted these results as evidence of Amicus’s transition from a cash-burning biotech to a profit-generating entity, a narrative that likely contributed to the 33% premium in the BioMarin offer.

The resolution of patent litigation for Galafold added another layer of strategic value. By securing exclusivity until 2037, the settlements removed a critical overhang that had previously constrained Amicus’s valuation. This outcome aligned with BioMarin’s focus on long-term portfolio stability, as extended market exclusivity for rare-disease therapies directly enhances revenue predictability. The deal’s all-cash structure and financing terms—leveraging $2 billion in BioMarin’s existing cash reserves and $3.7 billion in non-convertible debt—also signaled confidence in the acquisition’s risk profile, further solidifying investor confidence in the transaction’s completion.

Looking ahead, FOLD’s stock is now primarily priced as a merger arbitrage opportunity, with its $14.18 closing price on December 19 leaving a $0.32 gap to the $14.50 offer. Market participants are closely monitoring regulatory approvals, shareholder votes, and potential delays in the Q2 2026 closing timeline. While the immediate upside appears capped by the fixed cash price, the acquisition’s structural certainty and Amicus’s operational strengths position the stock to trade in a narrow range until deal execution. For now, the focus remains on the mechanics of closing rather than standalone biotech fundamentals.