Omnicom Slides 2.23% as $220M Volume Ranks 488th Amid Macro Pressures

On September 10, 2025, Omnicom Group (OMC) closed with a 2.23% decline, trading at a daily volume of $0.22 billion, ranking 488th in market activity. The drop follows mixed signals from recent developments affecting its core advertising and marketing services business.

Analysts noted heightened sensitivity to macroeconomic headwinds, particularly as global advertising budgets face potential compression amid shifting consumer spending patterns. A key factor cited was the company’s exposure to cyclical sectors, where recent earnings trends have shown volatility. While no immediate earnings reports or executive announcements were disclosed, industry observers highlighted the broader sector’s susceptibility to prolonged economic uncertainty.

The firm’s market position remains underpinned by its diversified portfolio of agencies, but recent market dynamics suggest investors are recalibrating risk appetites. This aligns with broader trends in the communications sector, where valuation multiples have contracted in response to macroeconomic pressures. No material corporate actions or regulatory developments were reported to directly impact Omnicom’s operations during the period.

To run this back-test rigorously I need to clarify two practical points: 1. Universe definition • “Top 500 stocks by daily trading volume” could mean: - The S&P 500 constituents (fixed list of 500 names); or - A rolling list that is re-selected every trading day from the entire U.S. equity universe based on that day’s volume. The second approach is closer to your wording but requires full-market data for thousands of tickers each day. 2. Portfolio construction • Equal-weight each day’s 500 names? • Or weight by something else (e.g., volume, dollar value, etc.)? My toolkit can handle a fixed universe (e.g., the S&P 500) very smoothly. For the “re-select 500 highest-volume names each day” version, I can implement it, but it will take longer to pull and process the full-market data set. Please let me know which of these two universes you’d like to use, and whether the portfolio should be equal-weighted. Once I have that, I can generate the retrieval plan and launch the back-test.