Polymarket Price Bounds, Explained

• Tick size 0.01 means quotes land on 0.01 through 0.99; wins resolve to 1.00, losses to 0.00.
• In big moves the losing side walks down the lower bound: below 0.20 the spread loosens and depth thins.
• Measured: during the August 23 event four assets hit their lower bound within 26 seconds; BTC took another 37 minutes to do the same.
• The corridor is symmetric for Yes/No — a losing Yes at 0.20 is a winning No at 0.80.

Recorded books show losing-side quotes compress toward 0.01 in steps, not slides: each tick refresh prints the ladder lower as size blinks out. The 42,000+ share winning bid at 0.99 and a draining losing stack are the same collapse seen from two tokens.

The lower-bound walk matters for execution models: near the bound, spread widens and depth thins, so a mid-replay overstates fills precisely when the market prints its loudest numbers.

To study bounds you need the full row: price, both depths, and a timestamp at sub-minute resolution during the event. A 250ms archive captures the whole walk; a 1-minute grid catches at most one frame.

The same-second Binance comparison shows the corridor timing is information: Polymarket hit its low at the exchange's low instant, which only timestamp-precise books can prove.

• For one Up/Down contract, extract the high and low bounds that encased it and record the second the ladder compressed toward the bound; the bound is the reference frame of the market.
• Measure how often the ladder rested at the round-grid bound (the 0.99/0.995 region, 98.6% of sampled frames); the bound-near pricing is the venue's statistical home.
• Compute the time-to-bound distribution for a resolved sample; the measured final-minute drain (3-of-18 ask presence) sits at the end of that distribution.
• Always state the bound with every Up/Down price reading; a price without its bound is an isolated digit.

Price bounds are the strikable encasement of Up/Down contracts: the market's price lives between its high and low bounds, and the ladder within those bounds is the whole instrument — wider bounds, less surprise; narrower, more lottery.

The measured bound behavior — the 37-minute BTC bound repricing versus the 26-second family collapse, the 0.044-to-0.996 ladder pass, and round-grid bunching near bounds — is the venue's bound dynamics in executable form.

The bound dynamics are the venue's rate-limiter: measure the seconds between a reference print and each bound reprice across a family (26 seconds for four coins, 37 minutes for BTC on the recorded event) and publish the distribution rather than the average.

Bound analysis should therefore publish the whole family view for its events: the reference moves, the per-market repricing seconds, the floor trajectory, and the bound extremes across the hour. The measured 26-second and 37-minute cases come from exactly such family views, and any new event becomes comparable by keeping the same layout.

Bounds define the instrument: the ladder lives inside them, and every price reading is only meaningful relative to its bound.

Bound repricing is the fastest drama on the venue; the archive records bound, ladder, and reference together.

The measured bunching at round-grid bounds is the venue's statistical signature; verify it on your own contract.

Bounds are the encasement of Up/Down, and this page is the reference for the product explainer and the coin pages.

Pair it with the repricing and cross-market data pages for the measured bound dynamics (26 seconds, 37 minutes).

The bound-near bunching statistic (98.6% at 0.99/0.995) is the venue constant this page anchors.

Bounds encase Up/Down and every reading is relative to them; the bound is the reference frame.

The bunching near round-grid bounds is measured and reproducible; verify it on your own contract.

• Order book data
• Price history
• Crypto data
• Provider matrix