Merck’s Stock Slides to 101st in Volume Amid Regulatory Scrutiny and Delayed Antiviral Trial Results

On September 12, 2025, Merck (MRK) traded with a volume of $830 million, ranking 101st in the market. The stock closed down 2.75%, reflecting mixed investor sentiment amid evolving market dynamics.

Recent developments suggest potential headwinds for Merck. Regulatory scrutiny over its pricing strategies for key oncology drugs has intensified, with analysts noting heightened uncertainty around future revenue streams. Additionally, a delay in the phase III trial results for its experimental antiviral candidate, which had been anticipated to bolster the pipeline, has raised questions about near-term therapeutic advancements. These factors appear to have contributed to the downward pressure on shares.

Market participants are also weighing in on Merck’s strategic direction. A recent executive statement emphasized long-term R&D commitments but offered limited clarity on short-term cost-cutting measures, prompting some investors to recalibrate expectations. The stock’s performance aligns with broader sector trends, where pharmaceuticals face dual challenges of patent expirations and pricing negotiations in key markets.

To build an accurate back-test for “buy the 500 highest-volume stocks each day, hold 1 day, from 2022-01-01 to today”, I need to pin down two practical details before proceeding: 1. Universe – Which market should we pull the 500 names from? • US-listed common stocks only (NYSE + NASDAQ + AMEX)? • A specific index membership list (e.g. Russell 3000 constituents)? • All global equities? 2. Trading assumptions – Do you want to include any transaction costs or treat trading as frictionless (i.e., no commissions, slippage, or bid/ask spread)? Once I have this, I’ll fetch historical volume data, form the daily baskets, and run the equal-weighted 1-day-hold test.