Middling
Middling is an arbitrage-adjacent strategy where you bet opposite sides of the same game at different point spreads. If the final margin lands in the "middle"—between your two numbers—you win both bets.
How Middling Works
Say you bet early in the week:
Monday: Bet Chiefs +7.5 at -110 ($110 to win $100)
The line moves during the week based on sharp action:
Friday: Bet Bills -3.5 at -110 ($110 to win $100)
Now you have both sides with a 4-point middle:
| Final Margin | Chiefs +7.5 | Bills -3.5 | Net Result |
|---|---|---|---|
| Bills by 1-3 | ✓ Win $100 | ✗ Lose $110 | -$10 |
| Bills by 4-7 | ✓ Win $100 | ✓ Win $100 | +$200 |
| Bills by 8+ | ✗ Lose $110 | ✓ Win $100 | -$10 |
| Chiefs win | ✓ Win $100 | ✗ Lose $110 | -$10 |
In most scenarios, you lose $10 (the vig on the losing side). But if the Bills win by 4, 5, 6, or 7? You win both sides for +$200.
The Math
Whether middling is +EV depends on:
- Size of the middle. Bigger middle = more outcomes where you win both.
- Probability of landing in the middle. Certain numbers (3, 7 in NFL) are more common.
- Vig paid. Each side costs vig.
Professional middlers model the probability of each final margin and calculate expected value. A 4-point middle in the NFL might hit ~15% of the time—enough to be profitable at standard juice.
Finding Middles
Middles require significant line movement:
Line shopping. Different books post different numbers. You might find +7.5 at Book A and -3.5 at Book B simultaneously.
Time arbitrage. Bet early, bet late. Lines move during the week as information emerges.
Key number hunting. NFL key numbers (3, 7) make middles around them especially valuable. Getting +7.5 to -6.5 is a middle around 7.
Middling vs True Arbitrage
| Middling | True Arbitrage |
|---|---|
| Bet both sides at different spreads | Bet both sides at guaranteed profit |
| Win both if middle hits | Guaranteed profit regardless |
| Lose vig if middle misses | No losing scenario |
| Requires line movement | Requires mispriced lines |
True arbitrage is rare and gets closed quickly. Middling is more accessible but carries risk.
Middling in Prediction Markets
On Kalshi and similar platforms, you can construct middles when prices shift:
Day 1: Buy YES at 40¢ Day 3: Sell YES at 50¢ (or buy NO at 50¢)
If the market ends up between your entry points, you've locked profit. This is closer to true arbitrage than sports middling because prediction market outcomes are binary.
Related Terms
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