polyshadow

NFL: High-Variance, Low-Frequency Swings

Markets analysed

7

Avg lead changes

3.1

per market

Avg probability swing

27%

winner min to loser max

One-sided markets

43%

never changed leader

NFL game markets are volatile but in a different pattern than NBA. Scoring is less frequent; a single touchdown can represent a 40% swing in win probability, meaning NFL markets have fewer total lead changes than NBA but larger individual jumps. A 14-point lead feels insurmountable until it doesn't.

The data shows NFL markets cluster into two groups: early blowouts that never reverse (high one-sidedness, no lead changes after the first quarter) and nail-biter games where the market oscillates across 0.5 multiple times. There are very few NFL markets with exactly one lead change: it tends to be zero or many.

Lead Changes

Lead Change Distribution

How many times did the market leader flip during the market's lifetime? Zero means one side dominated from open to close. Higher numbers mean contested, back-and-forth outcomes: the kind that create the most trading opportunity.

3
1
1
1
1
0
1
2
3
4
5
6
7
8
9+

Number of lead changes per market

Probability Ranges

Probability Range by Market

Each bar is one resolved market. The coloured zone spans from the winner's lowest point (left edge) to the loser's peak (white marker) — this is where a reversal was possible. The dim green tail extends from the loser's peak to 100%, where the winner eventually resolved. A wide red zone means the market was nearly overturned.

Reversal Timing

When Did Reversals Happen?

Each dot is a market that had at least one lead change. The x-axis shows when the last reversal happened as a percentage of the market's total lifetime. Points in the shaded red zone (75-100%) reversed in the final quarter, the highest-risk window for certainty sellers.

Trading Angle

NFL two-minute drills are statistically underpriced in Polymarket markets. Teams trailing by 8+ with 3 minutes left are frequently priced below their true conversion rate. Fourth-quarter possessions with timeouts remaining are particularly high-value spots to take the underdog.

Calibration

Calibration Curve

When a NFL market prices the favourite at 80%, does it actually win 80% of the time? Points below the dashed diagonal mean the market is overconfident. Each coloured line shows calibration at a different stage of the market's lifetime; systematic deviation is where the edge lives.

Perfect calibration50%60%70%80%90%100%0%25%50%75%100%Favourite's implied probabilityActual win rateEarly (10%)Midpoint (50%)Late (80%)
Upset Probability

Upset Probability Matrix

If the favourite is at X% at this stage of the market, how often does the underdog still win? Red cells are where the market is systematically overconfident. The Late (80%) row is the most actionable: this is where traders decide whether to fade certainty or follow momentum.

When evaluated50–60%60–70%70–80%80–90%90–100%
Early (10%)
100%
upset
3 markets
0%
upset
1 markets
0%
upset
1 markets
0%
upset
2 markets
Midpoint (50%)
67%
upset
3 markets
0%
upset
1 markets
0%
upset
1 markets
0%
upset
2 markets
Late (80%)
50%
upset
2 markets
0%
upset
2 markets
0%
upset
1 markets
0%
upset
2 markets
<5% upset
12–20%
20–30%
>30% (mispriced)
Smart Money

Where Smart Money Enters

Every $10,000+ trade on a NFL market plotted by two dimensions: what probability was the market at when the trade happened (x-axis), and how far through the market's lifetime it was placed (y-axis). Brighter cells mean more large-capital entries at that combination. A cluster at low probability early suggests informed contrarian positioning. A cluster at high probability late suggests momentum-following by large accounts.

0%10%20%30%40%50%60%70%80%90%Outcome probability at trade time0%10%20%30%40%50%60%70%80%90%% through market at trade timefewermore
Market Extremes

Most Dramatic Resolved Markets

Ranked by probability swing (the gap between the winner's lowest point and the loser's highest point). These are the markets where the eventual winner was most seriously challenged.

Act on these patterns in real time

Polyshadow signals fire when smart money bets match the patterns described above: late-money whale positions, new-account bets, and convergence across unconnected wallets.

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