ApexVol Terminal
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Open Interest and Volume
are activity metrics. Volume is contracts traded today. Open Interest is total contracts currently open (not yet closed or exercised).
High OI and volume indicate liquid options with tight spreads. Changes in OI show whether positions are being opened or closed.
Quick answer
Volume = contracts traded TODAY. Open Interest = total contracts OPEN. High both = liquid, easy to trade. Rising OI = new positions. Falling OI = positions closing. Check both before trading.
Volume counts contracts traded today; open interest counts contracts still open — together they are the clearest read on an option's liquidity.
Volume
Volume is the number of contracts traded during the current trading day. It resets to zero each day.
High volume means:
- Active trading interest today
- Easier to get filled
- Tighter bid-ask spreads
To see how volume differs across funds, compare the top ETFs by options volume.
ApexVol Terminal
Options analytics, live.
Chains, IV rank, expected move and dealer positioning for 5,500+ US stocks and ETFs.
- Live chains and Greeks
- IV rank and percentile
- Expected move and GEX
- Screener and strategy P&L
Free on AAPL, no account. Trial: no charge if you cancel before it ends.
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Open Interest (OI)
Open interest is the total number of contracts currently held by traders. It updates once daily (after market close).
OI increases when: New buyer and new seller create a contract
OI decreases when: Existing holder closes position with another existing holder
OI unchanged: When one party is new and one is closing
Volume vs OI: Key Differences
| Feature | Volume | Open Interest |
|---|---|---|
| Measures | Today's activity | Total open positions |
| Resets | Daily | Never (cumulative) |
| Updates | Real-time | End of day |
What to Look For
- Trade where OI > 100 (minimum)
- Prefer OI > 1,000 for liquidity
- High volume/OI ratio = active interest today
- Sudden OI spikes = big positions opening
Key Takeaways
- Volume = today's trades
- OI = total open contracts
- Both indicate liquidity
- High OI = easier to trade
Taught in Volcademy
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Options Profit CalculatorGet this number by API, or in Claude
Volume profile (get_volume_profile in an MCP client), Flow (get_options_flow in an MCP client), Smart money flow (get_smart_money_flow in an MCP client): one Bearer token, JSON back, the same tools an assistant calls through the ApexVol MCP server.
curl -H "Authorization: Bearer avmcp_YOUR_TOKEN" \
"https://apexvol.com/api/mcp/data/volume-profile/SPY"Which SPY strikes have the most volume today?
Claude calls get_volume_profileThe endpoint page has every parameter, a real captured response and a console that runs it on your ticker. Tokens come with every paid or trial plan.
- Written by
- ApexVol Research Team
Quantitative options research. All calculations use live institutional-grade data — the same source professional volatility desks use. - Reviewed by
- Ryan Silk, ApexVol Founder
Reviewed for technical accuracy. 10+ years trading options; built ApexVol's pricing engine, Greeks model and IV-rank methodology.
Revised as market conditions and institutional data change. Last revised 2025-01-21. How we research →
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