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Guides built from Polymarket data and 0xinsider's own records: what a share pays, what fees and spreads cost, how a wallet earns its grade, and how to read a sports market.
46 guides in all categories
Prediction market terms and trader metrics, each with a worked example.
Short answers to the questions new traders ask first.
American or decimal odds to implied probability and the no-vig fair price in cents.
What a share pays, how the order book sets the price, why odds pass 100%, and how combos pay.
A Polymarket share pays $1 if you are right and $0 if you are wrong, and its price has been a fair probability: shares bought at 70-80¢ won 75.7% of the time. Your costs are the spread, the fee and your order's size.
On October 11, 2026, the median NFL book on Polymarket held $969,355 within 5¢ of the price and the median tennis book held $5. The price on a market page is usually a midpoint; what you pay is the best ask, and the book shows how far your order will move it.
On October 11, 2026, 329 of 870 Polymarket sports games cost more than $1.28 to buy every side, and none cost less than $1. The excess is the overround, what it costs to trade a thin book. The price Polymarket displays is a different number.
Of 82,404 wallets with a settled Polymarket combo buy, 53.27% have never won one and 23.32% are ahead. Held to settlement and before fees, 2-leg combos returned 98.5 cents per dollar staked, and combos of 8 or more legs returned 56.5 cents.
Taker fees, rebates, and maker rewards, with the formula behind each.
Large soccer fills on Polymarket paid 1.92% of their dollars in fees from August 16 to October 10, 2026, and NFL fills paid 0.40%: most large football fills from mid-September paid no fee at all. The fee peaks at 50¢, makers pay nothing, and two rebate programs return part of it.
Among wallets snapshotted after September 12, 100 held 71% of the tracked taker rebates; the sample excludes 13,978 older snapshots.
On October 11, 2026, Polymarket offered $306,055 a day in liquidity rewards, and 41 of its 18,171 reward markets held 48% of it. The rewards go to resting limit orders inside a max spread at a minimum size, and capital cost and inventory risk come out of them.
What a wallet's grade, win rate, and track record do and do not say.
324 of 170,974 graded wallets held an S on October 11, 2026. What each letter takes, why fewer than half the wallets ranked in the A band hold an A, and why a wallet can have no grade at all.
mintblade banked $9.1 million on five settled markets and holds a C. How sample size changes what a record can tell you, and how 0xinsider's grader treats a short one, measured on 170,974 graded wallets.
Polymarket's profit figure counts positions that haven't settled, and a win rate says nothing about the size of the losses. Measured on 170,974 graded wallets: what sits behind each number in a trader's record, and which numbers to trust first.
A $100,000 buy is only as good as the wallet behind it. Graded at the trade, S, A and B wallets came in +0.50 points against the price on 161,128 Polymarket sports buys, within noise; in play they led D and F wallets by 2.45 points.
A new wallet, a large size, a long-shot price or a cluster of wallets can justify a closer look. None of them proves identity, intent, coordination, or inside information.
How much to stake, how to spread it, and how to grade the price you got.
Large sports buys by S-grade wallets won 68.3% at an average price of 67.1¢. Kelly sizes that at 3.6% of your bankroll, and Polymarket's sports taker fee cuts it to 0.3%. A real edge is usually that thin.
Bitcoin's $100K and $120K markets moved together week to week (r = 0.89); the House and Bitcoin did not. The median S-grade wallet kept 73.7% of its markets in one category and put about 30 times its typical stake into its biggest market.
A Polymarket price is a probability in cents. On sports markets it is usually close to fair: large buys from April to September 2026 paid 60.6¢ and won 60.9% of the time. Five checks show when a price is not.
The Falcons cost 26.5¢ a week before kickoff and 31.5¢ at the close: +18.9% of closing line value before the game started. Polymarket publishes no closing instant, so you pick the reference yourself, and fees come off the gross number.
NFL, elections, geopolitics, and the listed companies behind the industry.
Win 53 of 100 NFL spread bets at -110 and you keep $130 on $11,000 risked. Make the same 53 picks at a 50¢ price with no vig and you keep $600. The whole difference is the price you paid.
The 2024 presidential winner market traded $3.69 billion on Polymarket, and it is the hardest one to beat. The openings are early in the race, down the ballot, across state markets that move together, and in the order states count their votes.
A large bet from a wallet with no history is on chain the moment it executes. The record shows the trade, not the person or the reason. An alert shows you that trade while the market is still moving.
The numbers behind a sports trade, which wallets profit, and how to read the sharp money on a game.
Across 416,548 large Polymarket sports buys, buyers paid 60.6¢ on average and won 60.9% of the time, so the price is hard to beat. Each of the 8 numbers that decide a bet comes with its formula.
Of 49,118 Polymarket wallets with 20 or more settled sports markets, 43.7% were in profit on October 11, 2026 and the median wallet was $46 down. In the separate October 12 weighted read, wallets in profit and the rest pay about the same price, 57.7¢ against 58.5¢; the ones in profit beat it by 5.21 points on average. The data points to 7 habits.
Large buys under 10¢ on Polymarket sports markets won 3.53% of the time at an average price of 6.50¢; weighted by stake, a dollar returned 44 cents. Every bucket from 20¢ to 98¢ sat within two points of its price.
Of 401,482 large Polymarket sports bets, 48.6% landed after kickoff, and buys placed 1 to 7 days early lost 2.19 points to the price. From a day out through the final whistle, every timing bucket was calibrated.
In 1,150 Polymarket sports markets where 90% or more of the D and F wallets' money sat on one side before kickoff, that side trailed its price by 2.25 points, with an interval that reaches zero. The graded wallets' consensus was priced about right.
On Polymarket's settled totals neither side beat its price: Under buyers paid 58.4¢ and won 58.2%, and Over buyers paid 56.5¢ and won 55.6%. How often the Under lands depends on the line, and the price already reflects it.
Across 30,158 large Polymarket spread bets, laying the points came in 4.68 points ahead of the price and taking them came in 2.82 behind. Each line is its own market, and 29.1% of MLB games were decided by one run.
An NFL game on Polymarket now lists 43.9 markets that trade, up from 5.0 a year ago, and three market families still hold 98.4% of the money. Home teams won 53.7% of 566 settled NFL games; the interval includes 50%.
Polymarket reported $1.79 billion in volume on 2,229 MLB games in 2026, and 71.3% of it landed on the moneyline. The rest sits in totals, the run line, the first-inning market and player props, each with its own settlement rule and its own liquidity.
NBA home teams won 55.6% of 2,583 settled Polymarket games, and a study of 63,037 large NBA bets found no consistent gap between what buyers paid and what the games were worth. Read an NBA price as a fair estimate.
On 339 college football games in 2026, Polymarket reported $40.4 million in volume, 65.4% of it on the moneyline. Across 631 settled games, underdogs won 26.9% at an average kickoff price of 27.9¢, and across 985, home teams won 64.4%.
Of 17,953 settled Polymarket soccer matches, 25.9% ended level: 18.4% in the Champions League, 31.0% in Argentina. Polymarket lists each match as 3 markets, each team to win and the draw, and those 3 prices build double chance and draw no bet.
Both teams scored in 54.4% of 13,071 settled Polymarket matches: 63.4% in MLS, 44.6% in Argentina. When both scored, the match went over 2.5 goals 77.9% of the time, so the two markets usually land together.
The player who won the first set won 82.9% of 26,900 settled Polymarket tennis matches to October 10, 2026. The match, set and games markets each settle a retirement their own way, and a best-of-three match went to a third set 31.8% of the time.
A WNBA playoff game drew $686,386 in reported volume on Polymarket, 2.8 times a May game. Player props are the thinnest markets, about $207 a points prop, and the Under won 52% of them.
Across 9,501 CS2, Valorant, Dota 2, and LoL series ($1.82 billion in reported volume), the map 1 winner took the series 79.5% of the time, and 58.7% of series were swept 2-0. One CS2 series in 13 paid 50-50 in 2026.
Large buys on MMA favorites at 70¢ or more won 61.6% of the time at an average price of 80.4¢, and two upsets drive most of that gap. One UFC moneyline in nine paid 50-50 in 2026, and the moneyline drew 94.3% of fight volume.
Large buys on cricket favorites at 70¢ or more won 89.7% of the time at an average price of 85.1¢. The IPL drew 49% of 2026 cricket moneyline volume, and 99.8% of large cricket buys went on the moneyline.
Across 38,601 large Polymarket sports sells, exit prices were fair on average, within a point. You cash out by selling shares, all at once or in pieces, and one comparison decides whether to sell: the bid against your probability.
In the first hour of play since June 2026, S, A and B wallets came in at +2.23 points against their price and D and F wallets at -1.70, graded as of each trade. Before kickoff, the graded money confirms the price. Find where each group sits in 6 steps.
Reading Polymarket where it is blocked, tracking a wallet, trade alerts, followed wallets, wallet funding, and the public 0xinsider account.
Polymarket's help page says it is unavailable in 39 countries and lists 40. 0xinsider serves every Polymarket sports and esports market from its own servers, with wallet grades, the holders on each side, and recorded large trades. It takes no bets.
Every Polymarket wallet is public. Its address gives you every open position, every closed one, and the P&L behind them. This guide finds a wallet, reads its settled record, and follows it on 0xinsider, where an account follows 3 wallets free.
The large-trade feed recorded 9,400 Polymarket trades from September 20 to October 10, 2026, 940 on an average Sunday. An alert on category, size, grade or new wallets cuts that to the trades you want, in the app about five seconds after the fill.
Of 450 wallets followed on 0xinsider, 362 made no large trade from September 20 to October 10, 2026, and a follow's default notification fires only on large trades. What a follow sends, how fast, and how to tell a quiet wallet from a dormant one.
Every Polymarket wallet trades in pUSD on Polygon, so every deposit is public, and most of what looks like one is not. Read a wallet's funding on Polygonscan or a 0xinsider profile, and see what funding alerts catch and miss.
Yes. The account is 0xinsider-com on Polymarket, and anyone can open it. Check its markets, sides, prices, and results there, then use 0xinsider for the grades, large trades, and P&L around them.
Guides published since the tracks above were last arranged, newest first.
Most of the Polymarket API needs no key. Market lists, order books, prices, positions and live scores all answer an anonymous request. Only placing orders and your own account stream need a signed credential. This guide maps which service answers which question.
The leaderboard ranks graded wallets by the profit they have banked. Pricing lists what each plan includes.
