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EXTENDED ROBUSTNESS ANALYSES
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--- A. WINSORIZATION SENSITIVITY (5-day returns) ---
  None           : R²=0.0335, t_kurt= 13.76, t_pc= -3.59, sig=8/10
  0.5%           : R²=0.0510, t_kurt= 36.51, t_pc=-21.31, sig=10/10
  1% (baseline)  : R²=0.0529, t_kurt= 40.07, t_pc=-21.48, sig=9/10
  2.5%           : R²=0.0577, t_kurt= 43.66, t_pc=-21.32, sig=9/10
  5%             : R²=0.0619, t_kurt= 45.73, t_pc=-20.86, sig=9/10

--- B. NEWEY-WEST LAG SENSITIVITY ---
  1-Day | NW( 5): 4/10 significant at 5%
  1-Day | NW(10): 4/10 significant at 5%
  1-Day | NW(22): 4/10 significant at 5%
  5-Day | NW( 5): 9/10 significant at 5%
  5-Day | NW(10): 9/10 significant at 5%
  5-Day | NW(22): 9/10 significant at 5%

--- C. RANK-BASED INFORMATION COEFFICIENTS (stocks) ---
  1-Day | iv_atm_30d               : IC=+0.0140, t=   1.84, %>0= 52.2
  1-Day | iv_term_slope            : IC=-0.0013, t=  -0.25, %>0= 49.2
  1-Day | iv_skew_25d              : IC=+0.0200, t=   3.51, %>0= 53.1
  1-Day | implied_skewness         : IC=-0.0018, t=  -0.32, %>0= 50.3
  1-Day | implied_kurtosis_proxy   : IC=-0.0083, t=  -1.44, %>0= 49.0
  1-Day | pc_volume_ratio          : IC=+0.0133, t=   3.10, %>0= 54.2
  1-Day | pc_oi_ratio              : IC=+0.0071, t=   1.56, %>0= 51.0
  1-Day | net_gamma_exposure       : IC=-0.0107, t=  -2.17, %>0= 48.1
  1-Day | rv_daily                 : IC=-0.0004, t=  -0.06, %>0= 50.0
  1-Day | rv_w                     : IC=+0.0019, t=   0.28, %>0= 50.1
  5-Day | iv_atm_30d               : IC=+0.0085, t=   1.09, %>0= 53.0
  5-Day | iv_term_slope            : IC=+0.0328, t=   6.30, %>0= 54.6
  5-Day | iv_skew_25d              : IC=-0.0558, t=  -9.66, %>0= 41.9
  5-Day | implied_skewness         : IC=-0.0188, t=  -3.30, %>0= 47.4
  5-Day | implied_kurtosis_proxy   : IC=+0.0978, t=  16.77, %>0= 64.3
  5-Day | pc_volume_ratio          : IC=-0.0591, t= -13.81, %>0= 37.2
  5-Day | pc_oi_ratio              : IC=+0.0170, t=   3.63, %>0= 52.4
  5-Day | net_gamma_exposure       : IC=+0.1702, t=  33.99, %>0= 77.8
  5-Day | rv_daily                 : IC=+0.0161, t=   2.41, %>0= 52.7
  5-Day | rv_w                     : IC=+0.0120, t=   1.73, %>0= 51.2

--- D. DECILE SORTS (D10 - D1, 5-day returns) ---
  Implied Kurtosis          | Quintile (baseline) : ann.ret=  44.04%, Sharpe= 2.328, t=  19.84
  Implied Kurtosis          | Decile              : ann.ret=  52.08%, Sharpe= 2.185, t=  18.56
  Put-Call Volume Ratio     | Quintile (baseline) : ann.ret= -30.29%, Sharpe=-2.478, t= -21.80
  Put-Call Volume Ratio     | Decile              : ann.ret= -33.37%, Sharpe=-2.099, t= -18.47
  Volatility Skew (25d)     | Quintile (baseline) : ann.ret= -37.53%, Sharpe=-1.868, t= -15.92
  Volatility Skew (25d)     | Decile              : ann.ret= -52.51%, Sharpe=-1.896, t= -16.11

--- E. LEAVE-ONE-YEAR-OUT PANEL R² ---
  excl. 2010: 5D-ret R²=0.0537, HAR+IV RV R²=0.4852
  excl. 2011: 5D-ret R²=0.0535, HAR+IV RV R²=0.4810
  excl. 2012: 5D-ret R²=0.0537, HAR+IV RV R²=0.4831
  excl. 2013: 5D-ret R²=0.0538, HAR+IV RV R²=0.4800
  excl. 2014: 5D-ret R²=0.0529, HAR+IV RV R²=0.4833
  excl. 2015: 5D-ret R²=0.0514, HAR+IV RV R²=0.4922
  excl. 2016: 5D-ret R²=0.0520, HAR+IV RV R²=0.4844
  excl. 2017: 5D-ret R²=0.0547, HAR+IV RV R²=0.4839
  excl. 2018: 5D-ret R²=0.0469, HAR+IV RV R²=0.4861
  excl. 2019: 5D-ret R²=0.0540, HAR+IV RV R²=0.4858
  excl. 2020: 5D-ret R²=0.0505, HAR+IV RV R²=0.4142
  excl. 2021: 5D-ret R²=0.0557, HAR+IV RV R²=0.4817
  excl. 2022: 5D-ret R²=0.0500, HAR+IV RV R²=0.4786
  excl. 2023: 5D-ret R²=0.0532, HAR+IV RV R²=0.4883
  excl. 2024: 5D-ret R²=0.0572, HAR+IV RV R²=0.4895
  excl. 2025: 5D-ret R²=0.0573, HAR+IV RV R²=0.4900

--- F. PLACEBO TEST (features permuted within ticker) ---
  Actual R²: 0.0529 (N=119,081)
  Placebo R² over 10 draws: mean=0.000804, max=0.000982

EXTENDED ROBUSTNESS COMPLETE.