McKesson Surges 3.26% Amid DOJ Opioid Probe as Volume Falls 45% to 142nd Rank

McKesson (MCK) closed 3.26% higher on Sept. 26, with a trading volume of $0.62 billion, representing a 45.15% decline from the previous day’s activity and ranking 142nd among U.S. stocks by volume.

Recent developments highlight regulatory scrutiny as the Department of Justice announced an expanded investigation into McKesson’s opioid distribution practices. The probe, focusing on its role in the 2017-2020 national drug shortage crisis, has raised concerns over potential liability exposure. Analysts note the case could trigger a broader reevaluation of pharmaceutical supply chain accountability.

Market participants observed mixed institutional activity, with two large block trades totaling over $85 million executed in the final hour of trading. These transactions, attributed to undisclosed asset managers, contrasted with reduced retail participation amid ongoing earnings season volatility. The stock’s volume-to-cap ratio of 1.2% suggests limited short-term speculative interest.

To run this back-test robustly I need to pin down a couple of practical details: 1. Market universe • Should the “top-500” screening be applied to all primary-listed U.S. common stocks (≈ 4,000 names), or to a narrower universe such as the Russell 3000, S&P 500, or another exchange/region? 2. Weighting method • Equal-weighted (every selected stock gets 0.2 % of the day’s capital), or volume-proportional / value-proportional? 3. Transaction time & price • Do we assume we can rank the day’s volume using the current day’s closing data and execute at next day’s open (typical realistic assumption), or buy at the same day’s close? These choices affect both the data we pull and the way we form the trade signals. Let me know your preferences and I’ll generate the retrieval plan and run the back-test.