GUIDE · Does Buying No on Everything Actually Work?
Does Buying No on Everything Actually Work?
There is an idea that circulates in every prediction market community, in roughly this form: "most markets resolve No, so just buy No on everything and collect". It sounds like a loophole. It is the single most common strategy question asked of prediction market founders, and it has never been answered with arithmetic. This page does the arithmetic.
The claim comes in two halves, and both halves are true:
- "73% of markets resolve No." True as an observed base rate across many markets.
- "The average No price is already 73 cents." Also true, and this is the half that kills the strategy.
Put the two numbers next to each other and the loophole closes by itself.
The Arithmetic That Ends the Loophole
A NO share pays $1.00 when the market resolves No, and $0.00 when it resolves Yes. Expected value of a NO share is therefore:
EV = P(market resolves No) x $1.00
If 73% of markets resolve No, the expected value of a NO share, ignoring price, is $0.73. And the market already prices NO at 73 cents on average. Buying NO at 73 cents to receive an expected $0.73 is buying a coin at its fair value: zero edge before fees, negative edge after them.
The base rate is already in the price. That is the whole answer, and it is why nobody who runs the numbers publishes a "buy No on everything" guide: the strategy is its own counterexample.
The two claims are not in tension. They are the same claim stated twice, once as a probability and once as a price. A market that expects a 73% No chance prices NO at 73 cents. The crowd that sets the price already knows the base rate.
The Real $100 Wet-Run
The theory has been tested with real money, and the result is documented in a widely shared community thread (471 points, 276 comments, and no authoritative resolution anywhere). A trader ran the strategy with $100: buy NO across a basket of markets, hold to resolution. The result was a loss of roughly $5 over a month.
A $5 loss on $100 is a 5% monthly drawdown, and it is exactly what the arithmetic predicts once fees are included. The fees are the difference between zero edge and negative edge. On Polymarket, taker fees follow the quadratic model fee = C x rate x P x (1 - P), and on Kalshi the taker fee is round up(0.07 x C x P x (1 - P)). At the prices a NO buyer pays, those fees land on every position. Our Kalshi fee math guide shows why the fee share is never trivial.
The wet-run did not lose 5% because the strategy was implemented badly. It lost because the strategy is the base rate, and the base rate is priced.
When Buying No Is Not a Loophole, Just a Trade
None of this means NO is never the right side. It means NO is a position like any other, and it needs a reason beyond the base rate:
- A directional view that differs from the price. If you think a specific market is overpriced on YES, NO is the expression of that view. The view is the trade, not the side.
- Late-stage mispricing. Markets near resolution sometimes carry stale YES prices when the event has effectively already happened. The edge here is timing and information, not the base rate.
- Liquidity-providing NO orders. Resting a NO bid as a maker pays better fees (zero on Polymarket) and can capture the half-spread. This is a market-making trade, not a buy-and-hold strategy.
Each of these is a real trade with an edge argument attached. "Buy NO because most markets resolve No" is not one of them, because the price already encodes the argument.
The Base Rate, In Context
The 73% figure is useful despite all of this. It is the single best prior for a new market with no price: expect roughly a 73% chance the market resolves No. The prior is real, and it belongs in your reasoning. It just does not belong in your order.
If a market prices NO at 60 cents, the market is disagreeing with the base rate, and the base rate says NO is undervalued. If NO is priced at 85 cents, the market is already expressing a stronger-than-average No expectation. The comparison between the price and the base rate is where the thinking happens. The price itself is the crowd's answer, not the question.
For the deeper mechanics of how these prices form, including why the YES side and NO side always sum to $1.00 and what that means for arbitrage, see our guide on reading Polymarket order books.
FAQ
Q: Do most prediction markets resolve No?
A: Yes, the observed base rate is around 73%. Most binary markets resolve No because most proposed events do not happen.
Q: If most markets resolve No, why not buy No on everything?
A: Because the price already reflects the base rate. The average NO price is around 73 cents, so buying NO returns an expected 73 cents per share: zero edge before fees.
Q: What did the real $100 wet-run lose?
A: Roughly $5 over a month, documented in a widely shared community thread. The loss matches the arithmetic: zero edge before fees, negative after them.
Q: Is buying No ever a good idea?
A: Yes, when you have a view on a specific market that differs from its price. The base rate alone is not a view; it is already in the price.
Q: Does the 73% base rate have any use?
A: Yes. It is a strong prior for a new market with no price yet. Compare any market's NO price against it: a 60 cent NO is cheap relative to the base rate, an 85 cent NO is expensive.
Q: Do fees change the answer?
A: They make it worse. Fees turn a zero-edge strategy into a guaranteed negative one, which is why the wet-run lost money at roughly the fee rate.
Last updated: 2026-08-11