Overnight-Return Daytime-Reversal Frequency, Dollar-Neutral Long-Short on 30 US Large Caps (USEQ 1-DAY, Akbas-Boehmer-Jiang-Koch tug-of-war)

Cross-sectional, long-short, dollar-neutral equity strategy on USEQ daily bars, using OHLCV only. Each daily bar carries the overnight leg (open_t / close_{t-1}) and the intraday leg (close_t / open_t). Akbas, Boehmer, Jiang & Koch (JFE 2022, 'Overnight returns, daytime reversals, and future stock returns') document a pattern in these two legs. A daytime reversal of a NEGATIVE overnight return (NR day: overnight < 0, intraday > 0) shows informed daytime traders correcting overnight noise-trader selling. A daytime reversal of a POSITIVE overnight return (PR day: overnight > 0, intraday < 0) shows daytime traders leaning against overnight noise-trader buying. Stocks with a high frequency of NR days minus PR days over the past month earn higher returns over the next month, and stocks with low NR-minus-PR earn lower returns. The 'tug of war' is between overnight retail/sentiment flow and daytime institutional flow, and the daytime side is better informed. Universe, fixed ex ante (30 liquid, sector-diverse large caps, all with USEQ 1-DAY history from 1970-2012 verified in the catalog): JPM, AAPL, MSFT, AMZN, GOOGL, META, NVDA, BAC, XOM, CVX, JNJ, PFE, MRK, KO, PEP, PG, WMT, HD, MCD, DIS, INTC, CSCO, ORCL, IBM, T, VZ, CAT, BA, GE, UNH (all '.USEQ'). JPM is the primary/clock leg. A name enters the ranking only after it has lookback_days of its own history, so META (2012) and GOOGL (2004) join late. The score for stock i is TUG_i = (#NR days - #PR days) / lookback_days over the trailing lookback_days sessions. Every rebalance_sessions sessions, counted by bars rather than calendar dates, rank the eligible names by TUG. Go long the top k_per_side names and short the bottom k_per_side, equal dollar per name. The book is dollar-neutral, with 50% of equity gross per side and 100% gross total. The leverage multiplier stays at the config default; no leverage field is declared in the plan. This mechanism is new to the corpus. It is not price momentum (it is a sign-pattern frequency, not a return level), not short-term reversal, and not a calendar window: the trigger is an observed return pattern, and the rebalance is a bar-count cadence. Implementation notes for speed (two prior USEQ basket runs timed out): keep one bounded deque of +1/0/-1 day codes per name plus a running sum, so each bar is O(1). Rank only on rebalance bars, after all 30 legs have printed the same session (timestamp barrier), with a sort of 30 floats. Never rescan history. Inspiration: Akbas et al. 2022 JFE; Lou, Polk & Skouras 2019 JFE 'A tug of war: overnight versus intraday expected returns'.