Merck's Stock Surges 7.39% on $2.98 Billion Volume Ranking 28th in U.S. Equities

Merck & Co. (MRK) surged 7.39% on October 1, 2025, with a trading volume of $2.98 billion, marking a 66.85% increase from the previous day’s volume and ranking it 28th among U.S. equities. The pharmaceutical giant’s sharp rebound came amid renewed investor confidence in its pipeline advancements and strategic clarity following recent operational updates.

Analysts highlighted management’s emphasis on streamlining R&D expenditures and accelerating high-potential drug candidates, which signaled a shift toward capital efficiency. The stock’s performance also reflected broader sector momentum as investors positioned for potential regulatory clarity on upcoming FDA decisions related to Merck’s oncology therapies.

To run this back-test robustly I need to clarify a few practical details: 1. Universe Which market’s stocks do you want to rank each day? • All U.S.-listed equities (including ETFs and ADRs)? • Only the current S&P 500 constituents, or another index? • Something else? 2. Trade execution convention • Buy at today’s close and sell at tomorrow’s close (common for an “overnight” 1-day hold), or • Buy at tomorrow’s open and sell at tomorrow’s close? 3. Weighting & costs • Equal-weight each of the 500 names for the 1-day holding period? • Assume zero transaction costs/slippage, or would you like to include estimates? Once I have these three points I can fetch the necessary volume and price data, generate the daily signals, and run the back-test from 2022-01-03 (first trading day of 2022) through today.