Unusual Options Activity Scanner (Vol/OI Ratio, CBOE)

Scan 80+ S&P 500 stocks and major ETFs for unusual options activity — contracts where Volume > 3× Open Interest, a classic signal of informed institutional or insider positioning. Powered by CBOE's free public delayed-quote API (~15-20 min delay). No API key required.

What it detects

When options volume suddenly far exceeds open interest on a specific strike/expiry, it signals that new money is entering the market — often before a major price move, earnings beat/miss, M&A rumor, or macro event.

Classic signal: Vol/OI ratio ≥ 3.0

---

⚡ Run in 30 seconds

Click Start with defaults. The actor scans 80+ symbols concurrently and returns all options with abnormal volume.

To narrow the scan:

{
  "optionType": "calls",
  "minVolume": 1000,
  "volOiThreshold": 5.0,
  "maxDte": 30
}

---

Output fields

Field	Description
symbol	Underlying stock/ETF ticker
option_ticker	OCC option ticker (e.g. AAPL260819C00150000)
opt_type	C (call) or P (put)
strike	Strike price
expiry	Expiration date (YYYY-MM-DD)
dte	Days to expiry
volume	Today's contracts traded
open_interest	Existing open contracts
vol_oi_ratio	Volume ÷ Open Interest (the signal metric)
iv_pct	Implied volatility %
notional_usd	Total notional value (volume × mid × 100)
underlying_price	Current stock price
moneyness	ITM / OTM / ATM (±5% threshold)
delta	Options delta
gamma	Options gamma
theta	Options theta (daily decay)

---

Input parameters

Parameter	Default	Description
symbols	80+ S&P500+ETFs	Custom ticker list (leave empty for default scan)
volOiThreshold	3.0	Min Vol/OI ratio to flag as unusual
minVolume	500	Minimum contracts traded today
minOpenInterest	100	Minimum existing open contracts
optionType	both	both, calls, or puts
minIvPct	0	Min IV filter (e.g. 20 = exclude sub-20% IV)
maxDte	0	Max days to expiry (0 = no limit; 7 = weeklies only)
sortBy	vol_oi_ratio_desc	Sort by ratio, volume, notional, or IV
limit	200	Max results returned
concurrency	8	Parallel CBOE requests

---

Data source

CBOE's free delayed-quote CDN: cdn.cboe.com/api/global/delayed_quotes/options/{SYMBOL}.json

• Delay: ~15-20 minutes
• Requires: No API key, no login
• Coverage: All optionable US stocks and ETFs listed on CBOE

---

Pricing

Pay-Per-Event:

• $0.005 — per actor start (one-time)
• $0.0001 — per unusual option row returned

Run	Symbols scanned	Unusual results	Cost
Default scan (80 symbols)	80	~50 results	$0.010
Full S&P 500 scan	500	~300 results	$0.035
Daily scheduled run	80/day × 20 days	~50/day	$0.20/mo

---

Automated daily scan example

Schedule this actor daily (e.g. 9:45 AM ET after market open) via Apify Schedules. Combine with a webhook to Slack or Telegram to get unusual options alerts every morning.

---

Use cases

1. Pre-earnings positioning — Spot call sweeps on a stock 2-5 days before earnings
2. M&A speculation — Unusual call volume on small/mid-caps often precedes acquisition rumors
3. Macro hedging signals — Heavy put buying on SPY/QQQ signals institutional concern
4. Volatility plays — High IV + unusual volume = possible IV expansion trade
5. Dark pool correlation — Cross-reference with dark pool prints for confirmation
6. Daily morning scan — Start every trading day with an unusual options briefing

---

Limitations

• 15-20 minute delay (CBOE free tier) — not suitable for scalping or HFT
• CBOE data only; does not include all exchanges (AMEX, ISE, C2 excluded)
• Volume resets daily at market open
• Greeks (delta/gamma/theta) sourced from the same CBOE feed — use for directional context, not precision

---

Related actors (same author)

• SEC 13F Institutional Holdings QoQ Tracker — See what institutions actually hold
• Economic Calendar Tracker — Time your options trades around macro events
• Stock Earnings Calendar — Pre-earnings unusual options are common setups

---

Feedback

If this scanner helped you spot a trade, a quick review helps others find it: Leave a review