Market Maker Reference
This specification defines the ticker format for crypto price prediction markets. Use this as the authoritative reference for ticker generation and parsing.
Overview
Crypto prediction market tickers follow a standard Gemini format for price threshold contracts:
Code
Ticker Structure
| Component | Description | Example |
|---|---|---|
GEMI | Gemini prediction market prefix | GEMI |
Event | Underlying asset + optional duration + expiry datetime | BTC2603230800 or BTC05M2602251745 |
Contract | Price threshold condition | HI105000 |
Full Ticker Examples:
GEMI-BTC2603230800-HI105000(daily contract)GEMI-BTC05M2602251745-HI66750(5-minute contract)GEMI-BTC15M2602251745-HI66750(15-minute contract)
Event Format
The event identifies the underlying crypto asset and its expiry.
Structure
Code
Components
| Component | Format | Description |
|---|---|---|
UNDERLYING | [A-Z]+ | Crypto asset symbol (e.g., BTC, ETH, SOL, XRP) |
DURATION | 05M or 15M | Optional. Duration marker for 5-minute or 15-minute interval contracts. Omitted for all other durations. |
EXPIRY | YYMMDDHHmm | Expiry date and time in UTC |
Expiry Format
Code
| Position | Part | Description |
|---|---|---|
| 1-2 | YY | Year (e.g., 26 for 2026) |
| 3-4 | MM | Month (01-12) |
| 5-6 | DD | Day (01-31) |
| 7-8 | HH | Hour in 24hr UTC (00-23) |
| 9-10 | mm | Minute (00-59) |
Examples:
BTC2603230800= BTC expiring March 23, 2026 08:00 UTCBTC05M2602251745= BTC 5-minute contract expiring February 25, 2026 17:45 UTCBTC15M2602251745= BTC 15-minute contract expiring February 25, 2026 17:45 UTC
Duration Markers
For 5-minute and 15-minute interval contracts only, a duration marker is inserted after the underlying asset symbol:
| Duration | Marker | Format | Example Event |
|---|---|---|---|
| 5 minutes | 05M | {UNDERLYING}05M{EXPIRY} | BTC05M2602251745 |
| 15 minutes | 15M | {UNDERLYING}15M{EXPIRY} | BTC15M2602251745 |
| All others | (none) | {UNDERLYING}{EXPIRY} | BTC2603230800 |
Duration Marker Rules
- Only
05Mand15Mmarkers are supported (zero-padded to 3 characters) - All other durations (1 day, 1 week, etc.) omit the duration marker
- The marker
5Mwithout leading zero is not recognized—it must be05M
Supported Underlyings
| Asset | Symbol | Description |
|---|---|---|
| Bitcoin | BTC | Bitcoin price in USD |
| Ethereum | ETH | Ethereum price in USD |
| Solana | SOL | Solana price in USD |
| XRP | XRP | XRP price in USD |
Asset Availability
Additional assets may be added. Check the API Reference for the current list of available markets.
Contract Format
All Gemini crypto prediction contracts use the "greater than" (HI) price threshold format. This is the only contract type supported.
Structure
Code
Components
| Component | Description |
|---|---|
HI | Greater than (>) indicator |
PRICE | Strike price as integer, with D as decimal delimiter |
Price Encoding
- Whole numbers are entered as-is:
105000= $105,000 - Decimals use
Das delimiter:2D20= $2.20
| Price | Encoded |
|---|---|
| $105,000 | HI105000 |
| $2.20 | HI2D20 |
| $0.50 | HI0D50 |
| $3,500.25 | HI3500D25 |
Complete Examples
BTC Contract (Daily)
BTC > $105,000, expiring March 23, 2026 08:00 UTC
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | BTC |
| Expiry | 2603230800 |
| Contract | HI105000 |
| Full Ticker | GEMI-BTC2603230800-HI105000 |
BTC Contract (5-Minute)
BTC > $66,750, expiring February 25, 2026 17:45 UTC (5-minute interval)
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | BTC |
| Duration | 05M |
| Expiry | 2602251745 |
| Contract | HI66750 |
| Full Ticker | GEMI-BTC05M2602251745-HI66750 |
BTC Contract (15-Minute)
BTC > $66,750, expiring February 25, 2026 17:45 UTC (15-minute interval)
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | BTC |
| Duration | 15M |
| Expiry | 2602251745 |
| Contract | HI66750 |
| Full Ticker | GEMI-BTC15M2602251745-HI66750 |
XRP Contract
XRP > $2.20, expiring March 23, 2026 15:00 UTC
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | XRP |
| Expiry | 2603231500 |
| Contract | HI2D20 |
| Full Ticker | GEMI-XRP2603231500-HI2D20 |
ETH Contract
ETH > $4,500, expiring April 1, 2026 12:00 UTC
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | ETH |
| Expiry | 2604011200 |
| Contract | HI4500 |
| Full Ticker | GEMI-ETH2604011200-HI4500 |
SOL Contract
SOL > $250.50, expiring February 28, 2026 16:00 UTC
| Component | Value |
|---|---|
| Prefix | GEMI |
| Underlying | SOL |
| Expiry | 2602281600 |
| Contract | HI250D50 |
| Full Ticker | GEMI-SOL2602281600-HI250D50 |
Regex Patterns
Full Ticker
Code
Capture Groups:
- Underlying asset
- Duration marker (optional:
05Mor15M) - Expiry (YYMMDDHHmm)
- Price (with optional decimal)
Event Only
Code
Capture Groups:
- Underlying asset
- Duration marker (optional:
05Mor15M) - Expiry (YYMMDDHHmm)
Contract Only
Code
Validation Rules
- Ticker must start with
GEMI- - Underlying must be a valid crypto asset symbol
- Duration marker, if present, must be exactly
05Mor15M - Expiry must be a valid future UTC datetime
- Contract must start with
HI - Price decimal delimiter must be
D(not.)
Changelog
| Version | Effective Date | Changes |
|---|---|---|
| 1.1 | 2026-02-25 | Added duration markers for 5-minute (05M) and 15-minute (15M) interval contracts |
| 1.0 | 2026-02-13 | Initial specification |