28% — Harry Potter and the Philosopher's Stone Rotten Tomatoes score
Kalshi 28% · 17 contracts · $1 volume · medium confidence
Updated 2026-09-21 23:15:18 UTC

Why this matters:
This probability reflects market expectations that Harry Potter and the Philosopher's Stone will achieve a Rotten Tomatoes score above a specific threshold (the exact threshold varies by contract, ranging from 45 to 55 points). The current 20% probability suggests low conviction that the film will reach higher score levels. Key drivers include the critical reception patterns of recent fantasy adaptations, the original film's legacy reception versus modern critical standards, and how contemporary reviewers evaluate family entertainment relative to prestige cinema. The resolution depends entirely on the film's official Rotten Tomatoes score once sufficient critic reviews accumulate and the platform publishes its final aggregate rating. Market activity shows minimal recent trading volume on these contracts, indicating limited liquidity and potentially wider bid-ask spreads.

Key factors:
- Historical Rotten Tomatoes scores for Harry Potter films range from 80% (Prisoner of Azkaban) to 90% (Goblet of Fire), suggesting any new release could plausibly exceed 55%
- The threshold contracts show declining probabilities at higher score levels (55% scores 41¢ vs 45% scores 55¢), indicating market uncertainty about whether the film will land in upper-percentile critical reception
- Zero 24-hour trading volume suggests these markets lack active price discovery and may not reflect real-time consensus
- Critical standards for family fantasy films have shifted since the original 2001 release, affecting comparison benchmarks
- The film requires sufficient critic reviews to generate a final Rotten Tomatoes aggregate score, and timing of review publication will determine when resolution occurs

Contracts:
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 85 — 23¢ Kalshi $1 (weight 100%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 45 — 35¢ Kalshi $0 (weight 0%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 50 — 26¢ Kalshi $0 (weight 0%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 65 — 51¢ Kalshi $0 (weight 0%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 75 — 34¢ Kalshi $0 (weight 0%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 80 — 22¢ Kalshi $0 (weight 0%)
- Harry Potter and the Philosopher's Stone Rotten Tomatoes score?: Above 90 — 23¢ Kalshi $0 (weight 0%)
- Blade Runner 2099 Rotten Tomatoes score?: Above 45 — 80¢ Kalshi $0 (weight 0%)
- ... and 9 more

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## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

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*Last verified: 2026-09-21T21:20:49.614Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "28% per prediction markets (SimpleFunctions, September 2026)"
Canonical: https://simplefunctions.dev/answer/rttv
Full data: https://simplefunctions.dev/api/public/query?q=Harry%20Potter%20and%20the%20Philosopher's%20Stone%20Rotten%20Tomatoes%20score
Provider: SimpleFunctions — https://simplefunctions.dev