{
  "index_name": "Adverse Selection / Spread Pattern",
  "short_name": "Spreads",
  "as_of": "2026-02-28",
  "snapshot_note": "Cumulative snapshot from Paper 2. The negative coefficient indicates tighter, not wider, spreads in markets with flagged-wallet activity. This inverts the textbook Glosten-Milgrom prediction and is consistent with the Paper 1 finding that algorithmic market makers crowd into high-information-flow markets rather than retreating.",
  "source_paper": "Della Vedova (2026), 'Detecting Informed Trading in Prediction Markets'",
  "headline": {
    "n_markets_total": 204772,
    "n_markets_with_flagged": 65910,
    "share_markets_with_flagged": 0.32187017756333874,
    "mean_spread_in_flagged_markets": 0.4707012518127149,
    "mean_spread_in_clean_markets": 0.6433278079410528,
    "spread_gap": -0.17262655612833794,
    "regression_beta_has_sig_wallet": -0.1726265561283436,
    "regression_t_has_sig_wallet": -175.74708474953633,
    "direction": "tighter"
  },
  "regression_summary": [
    {
      "model": "(1) has_sig_wallet",
      "n": 204772,
      "beta_sig": -0.1726265561283436,
      "se_sig": 0.0009822442083426,
      "t_sig": -175.74708474953633,
      "R2": 0.1002481673693393
    },
    {
      "model": "(2) sig_fraction",
      "n": 204772,
      "beta_sig": -1.6738469857307168,
      "se_sig": 0.0772239700723952,
      "t_sig": -21.675225764248232,
      "R2": 0.0158332909397096
    },
    {
      "model": "(3) + Controls",
      "n": 204772,
      "beta_sig": -1.3539831810984673,
      "se_sig": 0.0665468079349601,
      "t_sig": -20.346327992498,
      "R2": 0.1257724988800267
    }
  ],
  "generated_at": "2026-05-11T21:07:28+00:00",
  "sources": [
    "G:\\My Drive\\1. Research\\1. Polymarket\\2. Insider\\output\\stage23_spread_regression.csv",
    "G:\\My Drive\\1. Research\\1. Polymarket\\2. Insider\\output\\stage23_market_spreads.csv"
  ]
}