Aon’s $240M Volume Lands It 445th in U.S. Market Activity

On October 3, 2025, Aon (AON) rose 0.85% with a trading volume of $240 million, ranking 445th in market activity across U.S. equities. The insurer's share price movement reflected investor focus on its strategic positioning in the evolving risk management sector amid broader market volatility.

Recent developments highlighted Aon's proactive approach to regulatory challenges in the European insurance market. The company announced a revised compliance framework to align with upcoming EU Solvency II reforms, signaling confidence in its ability to navigate regulatory shifts without compromising profitability. Analysts noted this proactive stance could differentiate Aon from peers facing similar compliance burdens.

Meanwhile, Aon's third-quarter earnings guidance, released days prior, showed cautious optimism. Management projected stable revenue growth in its risk solutions division, driven by increased demand for cyber risk assessments. However, cost-cutting measures in the corporate finance arm tempered overall expectations, prompting mixed reactions from institutional investors monitoring margin sustainability.

To run this back-test rigorously I need to confirm a few implementation details: 1. Universe - Should we use all U.S. common stocks (NYSE + NASDAQ + AMEX) that were listed on each day, or a narrower universe (e.g., Russell 3000 constituents)? 2. Ranking metric - "Daily trading volume" by (a) share count, or (b) dollar value (volume × price)? 3. Execution price assumption - Buy at today’s close and sell at tomorrow’s close (close-to-close return), or buy next day’s open and sell next day’s close (open-to-close)? 4. Trading costs - Ignore commissions and slippage, or apply a flat transaction cost (e.g., 2 bp each side)? Once those points are set I can fetch the data (volumes & prices), build the daily top-500 basket, and compute performance from 2022-01-03 to present. Please let me know your preferences so I can proceed.