Earnings Extrapolation and Predictable Stock Market Returns
Hongye Guo, 2025 · Review of Financial Studies
What the paper asks for.
The aggregate market return in newsy months (Jan/Apr/Jul/Oct, when earnings are announced) is predicted by past returns with the opposite sign of non-newsy months; investors extrapolate announced earnings, so a sign-flipped, expanding-mean-demeaned, vol-scaled time-series market-timing strategy earns a Sharpe near 0.50.
- Type
- technical
- Implementation
- pandas
- Rebalance
- monthly
- Long-short
- yes
- Data
- Bundled public task data
- Operational scope
- The paper-defined methodological core is retained; the fixed instruction instantiates only the data mappings, interfaces, and evaluation conventions needed for execution.
- 01 Data loading
- 02 Feature engineering
- 03 Model fitting
- 04 Signal generation
- 05 Portfolio construction
- 06 Execution
17 properties · 80 attempts.
Each row is one requirement the strategy must satisfy. The bar reports the share of observed checker verdicts that pass; missing checker output is not converted into a property verdict.
- A2no global normalize66/70
- A3no future data access64/70
- A4causal consistency63/70
- A6train test temporal order48/70
- A8transaction timing37/70
- A9signal delay test69/70
- A10e2e metric consistency0/70
- B1newsy month definition§§4 / Appendix C.1 “Group 1 contains January, April, July, and October... These newsy months largely correspond to the so-called 'earnings months'”provenance · paper-explicit69/70
- B2sum past four newsy returns window§Appendix C.1 “I take the total returns of the aggregate market in the past four newsy months (potentially include month t−1)”provenance · paper-explicit50/70
- B3expanding window mean computation§Appendix C.1 “compute its expanding window mean, which is the average from the beginning of the sample to month t−1”provenance · paper-explicit68/70
- B4demeaned signal sign flip§Appendix C.1 “I then take the difference, and flip sign if month t is newsy to arrive at the demeaned signal x_{t−1}”provenance · paper-explicit54/70
- B5constrained regression specification§Appendix C.1 “I then run a constrained time-series regression mkt_t = β x_{t-1} + 1·mkt_{t-1} + ε_t, where... the coefficient before mkt_{t-1} is constrained to be 1”provenance · paper-explicit53/70
- B6portfolio weight ct times xt§Appendix C.1 “The portfolio weight in my strategy is c_t x_t, which roughly has a mean of zero over time”provenance · paper-explicit51/70
- B7volatility scaling§Appendix C.1 “the portfolio is scaled by a constant so that it has the same volatility as the aggregate market, which is 5.34% per month”provenance · paper-explicit35/70
- B8monthly rebalance frequency§Appendix C.1 “at the end of each month t−1 I take the total returns of the aggregate market in the past four newsy months”provenance · paper-explicit53/70
- B9regression dependent variable total return§Appendix C.1 “constrained time-series regression mkt_t = β x_{t-1} + 1·mkt_{t-1} + ε_t, where mkt_t is the market return in month t”provenance · paper-explicit66/70
- B10expanding window regression reestimation§Table C1 note “regress the aggregate market return on lag one month signal and the expanding window mean aggregate market return based on data available in real time at each month, and with the coefficient on the expanding window mean aggregate market return constrained to 1”provenance · paper-explicit49/70
The lowest-passing observed requirement is e2e metric consistency: 0 of 70 observed checker verdicts pass. The full property list above shows whether errors concentrate in domain-level validity or the paper-specific strategy logic.