4 min read
Someone built a prediction market bot with a philosophy borrowed from the most cynical person at every dinner table—the one who always argues “nothing ever happens.” The bot, created by engineer Sterling Crispin, automatically buys "No" on every non-sports market on Polymarket it finds and holds to resolution. The entire trading strategy fits in one sentence.
Turns out, that might actually be enough to make your bags grow—kinda.
The premise rests on a number Polymarket publishes openly: 73.3% of all resolved markets on the platform end in "No." Crispin cited a nearly identical figure—73.4%—when he announced the bot on X earlier this week, a post that collected 3.1 million views.
Polymarket's own accuracy page confirms the data, explaining that "there are usually more ways for something not to happen than to happen in one exact way."
The observation cuts to something real about how prediction markets are built. Most questions on Polymarket are framed around specific events materializing by a deadline: Will a particular official resign, will a specific bill pass, will prices breach a round number. The status quo has a structural advantage—it only needs to hold, while the Yes outcome needs one precise chain of events to complete on schedule. When the deadline passes and nothing materializes, the bets on “No” collect.
The effect is amplified in longer-running markets. Our own quick analysis of over 2,300 closed Polymarket positions shows that markets open for 90 to 180 days resolve “No” at a rate of 73.5%, nearly matching the platform's overall published figure. Short-duration markets—under a week—flip closer to coin-toss territory, resolving "No" just 52% of the time (still a tiny advantage, but advantage nonetheless).
The longer a market stays open, the more time the world has to simply do nothing.
The bot is not, as some dismissive replies on Crispin's post assumed, just spraying capital at random. The source code reveals specific filters: It only targets non-sports markets, which have lower “No” rates, and only buys “No” when the best ask sits below $0.65. (All bets on prediction markets like Polymarket, Kalshi, or Myriad—operated by Decrypt’s parent company Dastan—resolve to $1, with users buying shares in a “yes” or “no” position at less than $1 per share and with the price implying current odds.)
That price cap does real work. Buying “No” at $0.40 only requires a 42% win rate to break even after gas fees on Polygon; buying at $0.60 pushes the break-even threshold to 59%. By capping entries below 65 cents (those with implied odds above 65%), the bot screens out markets where the crowd has already priced in the likely “No” outcome, and where the edge has evaporated.
The default 2% position sizing is a conservative default, not a limit—the bot allows any sizing up to 100%. At 10-20% sizing, annual returns reach 16-33%, which is competitive with active trading strategies.
Prediction markets have grown into a $63.5 billion-a-year industry, according to a 2026 CertiK report, and Polymarket was valued at $9 billion after NYSE parent Intercontinental Exchange invested $2 billion in October 2025. Markets of that scale don't leave exploitable inefficiencies sitting in plain sight for long.
The platform's top earners don't bet “No” on everything. Polymarket's all-time leaderboard shows the top 10 traders have collectively made over $113 million in profit—and nearly all of them are bettors with genuine domain expertise. Theo4, the leading wallet has made its own fortune on Yes/No political markets by placing odds in Yes or No depending on the event.
Image: Polymarket screenshot
The statistical edge Crispin identified is real. But turning it into a fortune requires more than a Python script set to "buy No."
The bot's edge (if any) comes from: Filtering for markets where “No” is priced below its true probability (the 65 cent cap), avoiding markets where “Yes” is underpriced (sports, finance) and selecting longer-duration markets.
The bot's GitHub repository is public, licensed CC0, and includes a live dashboard, a Heroku deployment guide, and a script called wallet_history.py for tracking realized performance. As of publication, Crispin has not shared his wallet address or actual profit figures from live trading.
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