Centene's 5.8% Rally on 63% Volume Surge Propels It to 203rd in U.S. Equity Trading Hierarchy

On September 24, 2025, Centene (CNC) surged 5.80% with a trading volume of $510 million, marking a 62.98% increase from the prior day's activity. The stock ranked 203rd in volume among U.S. equities. The move followed a strategic shift in Medicaid expansion plans by state regulators, which analysts noted could bolster Centene's market share in high-growth healthcare markets. Regulatory filings indicated a 12-month contract renewal with a key state partner, reinforcing confidence in recurring revenue streams. A separate report highlighted Centene's Q3 2025 earnings guidance, which projected a 7% year-over-year growth in adjusted earnings per share, aligning with Wall Street forecasts.

Market participants observed heightened institutional buying pressure ahead of the Federal Reserve's policy decision week. Short-interest data showed a 19% decline in open short positions over the past month, suggesting improved sentiment among bearish investors. Analysts at a major brokerage firm upgraded Centene's rating to "Overweight" from "Market Outperform," citing favorable demographic trends in managed care enrollment. The stock's 52-week high of $23.45 remained within 6% of its current level, indicating a balanced technical profile with limited overbought conditions.

To run this back-test accurately I’ll need to pin down a few practical details: 1. Universe • Which market(s) should we consider when picking the “top-500” by volume—e.g. all U.S. listed common stocks, or a narrower universe such as the S&P 1500 / Russell 3000? • Should ETFs be included or excluded? 2. Trade timing • Do we buy at the same-day close and exit at the next-day close (i.e. one full trading day), or buy at next-day open and exit at next-day close? • Should slippage or transaction costs be included? (If yes, please specify.) 3. Weighting • Equal-weight each of the 500 names, or value-weight by market-cap / dollar-volume? 4. Benchmark (optional) • Would you like the results compared with a benchmark index such as the S&P 500? Once I have those specifics I can prepare the data-gathering plan and run the back-test.