Regeneron Slides to 231st in Volume Amid Biotech Sector Turmoil as Tariffs and Cuts Reshape Market Dynamics

On August 6, 2025, Regeneron Pharmaceuticals (REGN) closed with a 2.59% decline, its trading volume of $0.48 billion placing it 231st among stocks on the day. The drop followed regulatory delays impacting high-dose Eylea applications due to a facility issue at a Catalent-owned site. CEO Leonard Schleifer indicated the company expects “favorable action” once the matter is resolved.

Broader industry pressures weighed on biotech sentiment. Trump’s proposed 250% pharmaceutical tariffs and ongoing FDA leadership instability raised uncertainty for drugmakers. Meanwhile, Merck’s $3 billion cost-cutting plan and BioNTech’s recent layoffs highlighted sector-wide cost-reduction trends. These factors, though not directly tied to Regeneron, contributed to a risk-off environment for biotech equities.

The strategy of purchasing the top 500 stocks by daily trading volume and holding them for one day returned 166.71% from 2022 to 2025, vastly outperforming the benchmark’s 29.18%. This highlights liquidity concentration’s role in short-term volatility, as high-volume stocks often reflect institutional and algorithmic activity more acutely than broader indices.