BBAI Plunges 3.6% on $1.88 Billion Surge in Volume, Climbs to 57th in Market Activity

On October 10, 2025, BigBear.ai Holdings (BBAI) closed at a 3.60% decline, with a trading volume of $1.88 billion—surpassing the previous day's volume by 69.44% and ranking 57th in market activity. The stock's performance reflected mixed investor sentiment amid evolving market dynamics.

Recent developments indicate heightened volatility in the AI sector as broader tech indices consolidate gains. Analysts noted that BBAI's trading activity aligns with a broader trend of speculative positioning in high-growth technology stocks, though liquidity constraints remain a concern given the stock's elevated volatility relative to peers. No material corporate announcements or regulatory updates were reported for the company during the period.

To run this back-test accurately I need to pin down a couple of practical details: Market / universe—Are we talking about U.S. listed equities (NYSE + NASDAQ), or another market? If the universe is very large, pulling every stock’s volume history day-by-day is data-heavy. To keep the task tractable we can either: Restrict to a subset (e.g., the Russell 3000, S&P 1500, etc.), or Work with a representative high-liquidity universe (e.g., constituents of SPY or QQQ), or Continue with the full U.S. market if you’re okay with longer processing time. Holding / rebalancing rule—Confirm you want to form the portfolio at each day’s close using that day’s top-500 by dollar volume, hold them for exactly one trading day, then rebalance the next day (i.e., 1-day holding period with daily turnover). Weighting scheme—Equal-weight each of the 500 names? Or volume-weighted / market-cap-weighted? Once I have these details I can start automating the data pull and back-test.