- 72% of all prediction market contracts resolve NO — confirmed across 161,000 contracts on Kalshi and Polymarket
- Buying NO at 50¢ has an EV of +$0.22 per contract assuming the 72% base rate holds
- The break-even NO price is ~72¢ — above this, category-specific NO rates must exceed the baseline
- Weather tail brackets: 80–95% NO. Geopolitics: 72–78%. Sports: 50–60% — size exposure accordingly
- NO-scanner filters: price (1–15¢ YES fades or 90¢+ bond harvesting), category priority, Maker execution only, 25% category cap
- Main risk: correlated tail events. Defense: strict position sizing and category diversification
The Number Behind the Strategy
Analysis of over 161,000 contracts across Kalshi and Polymarket produced a number that now drives every Beatpoly strategy: 72% of prediction market contracts resolve as NO.
This is not a Polymarket quirk or a Kalshi artifact — it appears across both platforms and across market categories. A calibration study of 8,476 Kalshi markets found a YES resolution rate of only 28.7% (71.3% NO). A Bloomberg analysis of 300+ Trump-related Polymarket contracts found the identical 72% NO rate. Aggregated data from 15,000+ Metaculus questions shows a slightly lower but consistent 63.5% NO baseline.
72% of prediction market contracts resolve NO across 161,000 analyzed contracts. This is the foundation of every systematic strategy on this site.
Why "Nothing Ever Happens"
The 72% NO rate reflects a fundamental truth about prediction markets: they systematically overestimate the probability of change, action, and dramatic outcomes. Two cognitive forces drive this:
Status Quo Bias
Retail traders eagerly buy YES on dramatic narratives — sudden resignations, military actions, extreme weather, shock policy changes — at prices far exceeding their true statistical probability. The market price of excitement consistently exceeds the mathematical price of the event.
Neglected Base Rate
Traders price contracts based on salient narratives rather than historical frequencies. The question “what usually happens in situations like this?” is almost never asked. Base rates are systematically underweighted. The base rate answer is almost always: nothing unusual happens. The market prices otherwise.
The EV of Systematic NO Buying
If the true probability of NO is 72%, what is the EV of buying NO at various prices?
| NO Purchase Price | True NO Probability | EV per Contract | EV per $100 Invested |
|---|---|---|---|
| 50¢ | 72% | +$0.22 | +$44 |
| 60¢ | 72% | +$0.12 | +$20 |
| 70¢ | 72% | +$0.02 | +$2.86 |
| 75¢ | 72% | −$0.03 | −$4 |
| 80¢ | 72% | −$0.08 | −$10 |
The break-even price is approximately 72¢ — buying NO above this price requires the specific sub-category to have a NO rate higher than the 72% baseline to remain profitable. In practice, geopolitical and policy markets consistently exceed 72% NO, while sports markets often fall below it.
Category-Level NO Resolution Rates
The 72% baseline is not uniform across all market types. Understanding the category distribution is essential for applying the scanner correctly:
| Category | Historical NO Rate | Strategy Implication |
|---|---|---|
| Geopolitical/Policy | ~72–78% | Strongest NO harvesting edge |
| Economics (macro) | ~60–75% | Efficiently priced by professionals — require stronger edge |
| Entertainment/Pop Culture | ~65–70% | Good edge, less professional competition |
| Weather (tail brackets) | ~80–95% | Best edge via Free Donut and 88¢ Rule |
| Sports | ~50–60% | Weaker edge, near coin-flip |
The NO-Scanner: Practical Selection Criteria
Buying NO indiscriminately at the 72% baseline is not a strategy — it is an approximation. Systematic NO harvesting uses specific filters to identify contracts where the edge is highest:
- Price threshold: Target YES prices between 1–15¢ (longshot fades) or buy NO when YES trades above 90¢ (bond harvesting). Avoid the 20–80¢ range unless you have specific model data.
- Category filter: Prioritize geopolitics and policy markets. Avoid sports and macro economic data, which attract professional participants who narrow the edge quickly.
- Execution: Always Maker (limit orders). Never market orders. The 32% vs. 10% average loss gap between Takers and Makers (Bürgi et al.) is the margin between profitable and unprofitable systematic trading.
- Diversification: Cap exposure in any single category at 25% of capital to avoid correlation risk — the main tail risk is a correlated black swan that invalidates base rates across many markets simultaneously.
The Main Risk: Correlated Tail Events
Systematic NO harvesting is structurally similar to selling deep out-of-the-money options. The P&L profile is: many small wins, occasional small losses, and rare catastrophic losses. The catastrophic scenario is a genuine paradigm-shifting event — a pandemic, a regional war, a financial crisis — that simultaneously validates many previously implausible YES contracts across unrelated markets.
When a genuine structural change occurs — a legitimate regime transition, a systemic shock — the base rate assumption breaks down across many markets at once. This is the primary risk of systematic NO harvesting. Position sizing (¼ Kelly, 5% single-market cap, 25% category cap) is the only defense. Do not confuse normal variance with a regime change, but do not dismiss large correlated moves as noise either.
Frequently Asked Questions
No. The 72% baseline means randomly selected NO contracts have a structural edge over YES, but the NO contract price must be below 72¢ to give you positive EV. If the market has already priced NO at 80¢, buying it at that price has negative EV (0.72 − 0.80 = −$0.08). The edge is in finding NO contracts mispriced below their true probability.
Two structural forces: (1) The Favorite-Longshot Bias — humans overweight dramatic, narrative-driven outcomes. (2) The supply-side imbalance — more retail participants buy YES on exciting events than provide liquidity on boring NO contracts. Market makers price this demand premium into the YES side.
Polymarket is the primary venue for systematic NO harvesting due to its volume depth in political and macro markets and its historically zero maker fees. Kalshi is better for the weather-specific variants (Free Donut, 88-Cent Rule) due to its MECE bracket structure and collateral return mechanics.