United Rises 1.08% Amid 23.8% Volume Drop as Stock Clings to 281st Rank in Trading Activity

On September 24, 2025, United (UTHR) closed with a 1.08% increase, trading on $370 million in volume—a 23.81% decline from the previous day’s turnover. The stock ranked 281st in trading activity among listed equities, indicating moderate liquidity but limited broader market engagement.

Analysts noted that recent regulatory clarity in the biotech sector contributed to a cautiously optimistic investor sentiment. While United’s volume contraction suggests reduced short-term speculative activity, its price resilience against broader market volatility highlights underlying demand from long-term holders. The stock’s performance appears decoupled from macroeconomic trends, with analysts attributing the move to sector-specific catalysts rather than broad market rotations.

To run this back-test rigorously I need to nail down a few practical details first: 1. Universe. • Do you want all U.S. listed common stocks (≈ 5 000 names) or a different universe (e.g., S&P 500 constituents)? 2. Weighting. • After selecting the top-500-by-volume on a given day, should the portfolio be equal-weighted, value-weighted, or something else? 3. Trade price. • Buy at today’s close and sell at tomorrow’s close (the usual approach), or buy tomorrow’s open and sell tomorrow’s close? 4. Tool limitations & workaround. • The back-testing engine we can invoke natively is designed for single-ticker strategies. To study a 500-stock daily-rebalanced portfolio we’ll have to build an aggregate “index” of the strategy’s returns behind the scenes and then run the engine on that synthetic index. • I can construct that synthetic index for you, but it will require retrieving daily data for every stock in the universe, which adds a little time. Let me know your preferences on items 1-3 (or confirm the defaults below), and I’ll start building the data and running the back-test right away: Default assumptions if I don’t hear otherwise: • Universe: all U.S. listed common stocks. • Weighting: equal-weight each day. • Execution: buy at today’s close, sell at next day’s close. Please confirm or adjust these assumptions.