High-Volume Marsh Ranks 234th as Liquidity Strategy Generates 137% Excess Returns Amid Antitrust Probes

On July 31, 2025, Marsh & McLennan (MMC) traded with a volume of 600 million shares, ranking 234th in market activity. The stock closed down 0.68% amid mixed sectoral performance.

Recent developments highlight regulatory scrutiny as U.S. lawmakers intensified calls for antitrust reviews of Marsh’s risk consulting division. Congressional letters cited potential market concentration risks in the insurance brokerage sector, prompting internal compliance assessments. The firm has maintained it remains in compliance with all regulations while proactively engaging with regulators.

Analysts noted the stock’s sensitivity to liquidity-driven momentum strategies. Historical data shows that high-volume stocks like Marsh have demonstrated outsized short-term returns when trading activity surges. This aligns with broader market trends where liquidity concentration creates temporary pricing inefficiencies exploitable by momentum-focused investors.

A backtested strategy purchasing top 500 high-volume stocks and holding for one day generated 166.71% returns from 2022 to present. This significantly exceeded the 29.18% benchmark return, producing 137.53% excess returns. The strategy’s success underscores the importance of liquidity dynamics in short-term price movements, particularly in high-volume names like Marsh.