AT Tumbles 2.44% on $1.06B Volume Ends 122nd in U.S. Equity Rankings

AT closed at a 2.44% decline on October 1, 2025, with $1.06 billion in trading volume ranking it 122nd among U.S. equities. The stock's performance reflected mixed signals from regulatory and operational developments, with no single catalyst dominating market sentiment.

Regulatory scrutiny remained a key theme as antitrust proceedings against the company's broadband division advanced in federal court. While no immediate penalties were announced, legal experts noted the case could influence future capital expenditure decisions. Separately, the company confirmed ongoing network modernization efforts, though details on 5G expansion timelines were deferred to Q4 earnings disclosures.

Market participants observed limited technical momentum as the stock failed to break above its 50-day moving average. Institutional selling pressure was noted in pre-market hours, though retail participation remained neutral. Analysts emphasized that volume levels remained within historical norms for this sector during earnings cycles.

To run this back-test robustly I need to clarify a few practical details: 1. Universe • Should we limit the universe to a specific exchange (e.g., all NYSE + NASDAQ common stocks) or literally every U.S.-listed stock? • Do ADRs, ETFs and preferred shares stay in or should we filter them out? 2. Re-balancing mechanics • You mentioned "top 500 by daily trading volume." – Do we rank on the previous day’s dollar volume (shares × close) and enter at the next day’s open? – Or do we rank in the morning on the same day’s pre-open volume forecast and enter at that day’s open (hard to implement realistically)? • Exit price after one trading day: next day’s close or next day’s open? 3. Transaction assumptions • Slippage/commissions: assume zero, a fixed per-share cost, or a bps spread? 4. Portfolio accounting • Equal-weighted across the 500 names each day? • Re-invest 100 % of capital each day (i.e., portfolio fully turns over daily)? Once I have these points, I’ll set up the data pull, generate the daily trade signals, and run the portfolio back-test from 2022-01-01 through today.