What are Polymarket Up/Down markets? A data-first explainer

Polymarket's Up/Down markets are the fastest prediction markets on the platform: every five minutes, a fresh binary market opens asking whether Bitcoin (or Ethereum) will close the round higher than it started. Traders buy Up or Down shares priced between $0.00 and $1.00; at resolution the winning share pays exactly $1.00 and the losing share pays nothing.

Round mechanics

• A new round opens every 5 minutes (a 15-minute variant ran in early 2026), around the clock — 288 BTC rounds per day.
• The share price is a live probability estimate: an Up price of 0.56 means the market collectively prices a 56% chance the round closes higher.
• Up and Down prices are complementary — they sum to roughly $1.00, with the gap reflecting the spread.
• At expiry, resolution is mechanical: the reference price either closed higher or it didn't.

What the ticks show

In tick data, a typical round opens near 0.50/0.50 and spends its first minutes hovering there — five-minute crypto moves are genuinely hard to predict. As the clock runs down, the remaining uncertainty shrinks and prices migrate toward the rails. The final thirty seconds are the signature of this market type: the winning side accelerates toward $0.99 while the loser collapses, because at that point the outcome is nearly determined and shares converge to their terminal value.

The day pages in the BTC 5-minute datasetquantify this: an average round's Up price spans a ~60–65¢ range from open to close, and the lead between Up and Down flips multiple times in volatile rounds before the late-round convergence kicks in.

Why researchers like this dataset

• Naturally labelled outcomes. Every round self-resolves within minutes, producing tens of thousands of clean binary labels — no manual annotation.
• A complete probability path. Each file is the full life of one market: how a crowd-priced probability evolves under a hard deadline.
• Microstructure at expiry. With orderbook depth snapshots, you can watch liquidity reposition as resolution approaches — rare data for binary markets.
• High sample density. 288 independent rounds per day per asset accumulate statistical power quickly, as in our win-rate analysis.

Working with the data

Each round is one CSV with ~150–200 ticks: timestamp, Up price, Down price and minutes remaining. The schema and ready-to-run pandas loaders live in the data format reference, and every dataset page offers a free full-day sample to experiment with before considering the complete archive.