FIELD GUIDE · BTC UP OR DOWN · 15 MINUTES

Read the market before the market reads you.

A practical guide to the 15-minute Bitcoin direction market—what decides the winner, why the display can lag, how orders get filled, and what automated traders are doing.

60 + 60 BRTI samplesExamples use ¢ per shareNo live prices
BTC Up or Down · 15mILLUSTRATION
PRICE TO BEAT FINAL MINUTE
reference feedthresholdsettlement zone
00:00 OPEN05:0010:0015:00 SETTLE
Price to beat$—,—
Winning sideUP ↑
01 / RULE

Outcome, not spot BTC

You trade a $0–$1 share that resolves to 0 or 1—not Bitcoin itself.

02 / PRICE

¢ means probability

A 63¢ Up share costs $0.63 and pays $1 only if Up wins.

03 / EXECUTION

Price and fill differ

The chart is context. The order book decides your actual entry and exit.

04 / SETTLEMENT

Sixty prints, twice

Opening-minute and final-minute BRTI averages decide the outcome.

01

Settlement

The winner comes from two one-minute averages—not one closing tick.

For these 15-minute BTC markets, settlement compares the simple average of 60 CF Benchmarks BRTI prints in the final minute before the endpoint with the simple average of 60 BRTI prints in the opening minute. Final average ≥ opening average means Up; otherwise Down.

Opening minuteAverage 60 prints

One BRTI print per second forms the opening baseline.

→
Middle 13 minutesMarket trades

Up and Down shares change hands while the outcome remains open.

→
Final minuteAverage 60 prints

Final average ≥ opening average: Up. Otherwise: Down.

!
This is not “closing spot price.”

No single exchange print and no single last-second tick decides the market. Averaging 60 readings on each side damps a brief spike: it can influence one or several samples without replacing the other readings in that minute.

UP SHARE

Bought at 62¢

If Up wins, one share settles at $1. Gross profit is 38¢. If Down wins, the share settles at $0 and the 62¢ stake is lost.

win P&L = $1.00 − $0.62 = +$0.38
DOWN SHARE

Bought at 27¢

If Down wins, one share settles at $1. Gross profit is 73¢. If Up wins, the share settles at $0 and the 27¢ stake is lost.

breakeven ≈ 27% before fees

What “tie goes to Up” means

Because the rule uses greater than or equal to, exactly equal opening and final averages resolve Up.

What BRTI combines

The BRTI composite includes eligible data from Coinbase, Kraken, Bitstamp, and Gemini. Binance.US is not a component. A lone venue drifting away from the composite does not create a settlement arbitrage.

02

The chart

Three numbers matter: reference value, threshold, and share price.

The BTC line visualizes reference movement; the Up/Down prices show the executable prediction market. They answer related—but different—questions, and they do not necessarily update at the same speed.

How to read one 15-minute windowILLUSTRATIVE · NOT LIVE
OPENING THRESHOLD below ≠ certain Down above at close → Up 00:0005:0010:0015:00
reference BTC pathopening thresholdfinal minute
A

Reference line

A visual trace of the BTC reference. It is context, not the actual order price and not the settlement calculation itself.

B

Opening baseline

The “price to beat” represents the opening-minute BRTI average used in the final comparison.

C

Outcome price

Up and Down prices come from bids, asks, and fills in the order book. They express what traders will pay now.

≠
The displayed chart can lag the live feed and the book.

Book prices can move first as automated traders process the BRTI feed. For the tradable state, trust the current bid and ask over a lagging chart. For settlement, trust the final BRTI averages—not either visual display.

CEX-agreement filter: an analysis safeguard, not a market rule

A CEX-agreement filter checks whether the relevant component exchanges broadly agree before treating a move as reliable. “Fail closed” means no agreement—or missing data—produces no valid signal. It does not alter settlement, and a divergence on one venue is not automatically an arbitrage.

03

The order book

The book is a queue of intentions. A trade happens only when prices cross.

Buyers post bids. Sellers post asks. The highest bid and lowest ask form the market’s inside quote. Their difference is the spread.

UP order bookCLICK A ROW
PriceSharesTotal
SPREAD2¢
USD
qty
Maximum cost$61.00
Profit if Up wins$39.00

Educational calculator only. It does not place an order or include fees.

Depth and slippage

If only 180 shares are offered at 64¢, a larger immediate buy must reach higher asks. Your average fill gets worse as your order “walks the book.” That difference is slippage.

Queue position

A resting order may sit behind older orders at the same price. Touching your price does not guarantee a fill; there may not be enough opposing volume to reach you.

04

Buy, sell, limit

Choose whether price certainty or execution certainty matters more.

A limit says, “fill me only at this price or better.” An immediately marketable order says, “use available liquidity now, up to my protection price.” Under the hood, Polymarket’s order system expresses orders as limits.

LIMIT BUY

Set your maximum entry

A 40¢ buy can fill at 40¢ or lower. If the best ask is 43¢, it rests until a seller reaches your price—or you cancel.

100 shares × $0.40 = $40 max cost
LIMIT SELL

Set your minimum exit

A 72¢ sell can fill at 72¢ or higher. It may fill partially, remain open, or never fill before the short market closes.

100 shares × $0.72 = $72 proceeds
MARKETABLE BUY

Cross the spread

Pay the best available ask for speed. Large orders may consume several price levels, so inspect depth—not just the top line.

urgency ↑ · price control ↓
POST-ONLY

Guarantee maker behavior

A post-only limit is rejected if it would trade immediately. It is useful when you want to add liquidity rather than take it.

crosses book → rejected, not filled

Order lifetimes in the API

  • GTC: good until filled or cancelled.
  • GTD: expires at a specified time.
  • FOK: fill the whole amount immediately or cancel all of it.
  • FAK: fill what is immediately available, then cancel the remainder.
⏱
In a 15-minute market, an unfilled order is a position decision.

Near expiry, the reference can move faster than you can cancel and replace. A stale resting quote may be filled precisely because new information made it bad for you—called adverse selection.

05

Bots

Automation changes speed and consistency—not the contract.

Bots can consume BRTI and exchange data, place or update quotes, cancel stale orders, or react to book changes faster than a human. They still use the same order book and settle under the same 60-print-average rule.

Market-making bots

QUOTE BOTH SIDES

Place bids and asks around a fair value, trying to capture the spread. Their main risk is being filled just before fair value moves against them.

Execution bots

ENTER / EXIT

Break an order into pieces, enforce price limits, cancel after a deadline, or reduce slippage. They improve discipline, not prediction.

Feed-monitoring bots

READ SOURCES

Read the BRTI and its component venues, maintain rolling opening and final-minute averages, and estimate what the settlement calculation currently contains.

Reaction bots

FOLLOW UPDATES

Respond to visible trades, quote changes, or feed movement. Their actions can make the book move before a slower chart redraws.

Latency risk

Your view of the feed or book may already be stale when the order reaches the matcher.

Cancel risk

A cancel request can race with a fill. Treat a live order as live until cancellation is confirmed.

Partial fills

A bot may fill only part of the desired position, leaving unexpected directional exposure.

Reference mismatch

Following a single CEX instead of the BRTI composite can disagree with the data that actually settles the market.

Display lag

A bot can process new data and reprice orders while a human-facing chart still shows an older frame.

06

Glossary

The small vocabulary that unlocks the whole screen.

Ask
The lowest price a seller is currently offering.
Bid
The highest price a buyer is currently offering.
Spread
The difference between best ask and best bid.
Depth
Available size at each price level in the book.
Maker
A trader whose resting order adds liquidity.
Taker
A trader whose order immediately matches resting liquidity.
Slippage
The gap between expected and average executed price.
Partial fill
Only some of the requested shares execute.
Implied probability
A rough reading of share price as odds: 61¢ ≈ 61%, before market frictions.
Adverse selection
Getting filled because the other side has newer or better information.
Price to beat
The opening-minute BRTI average used as the round’s threshold.
BRTI
CF Benchmarks’ Bitcoin Real-Time Index, the composite reference used by this market’s settlement rule.
Resolution
The process that compares the two one-minute averages and determines the $1 outcome.