Every trading day, millions of options contracts change hands across U.S. exchanges. Most of this activity is routine — market makers adjusting hedges, retail traders opening small positions, algorithms executing spreads. But some trades stand out. That's what traders call "unusual options activity" — or sometimes "unusual option activity."
What Makes Options Activity "Unusual"
There's no single definition, but most options flow scanners flag activity based on a combination of these signals:
Volume vs. Open Interest
This is the most straightforward indicator. If a contract normally has 200 open interest and 50 daily volume, but today it trades 5,000 contracts, something changed. A high volume-to-open-interest ratio suggests new positions being opened — not existing ones closing.
Premium Size
A $2 million bet on a single options contract is more significant than a $2,000 one. Large premiums signal conviction and typically come from institutional traders or well-capitalized participants who've done their homework.
Sweep Orders
A sweep order hits multiple exchanges simultaneously to get the fastest fill possible. When a trader is willing to sweep across CBOE, PHLX, MIAX, and others — paying slightly different prices at each — it signals urgency. They want the position, and they want it now.
Strike and Expiration Choice
Out-of-the-money options with large premiums are noteworthy because they need a significant price move to become profitable. When someone puts $1M into 20%-OTM calls expiring in two weeks, they're either hedging something specific or expecting a major catalyst.
Short-dated options with large premiums are similarly meaningful — the buyer is paying for time decay risk, which only makes sense if they expect something to happen soon.
What Unusual Activity Can Tell You
When you see a cluster of unusual activity — multiple large trades in the same name, same direction, within a short window — it often precedes a move. This could be:
- Earnings positioning — Large call or put activity ahead of an earnings report
- M&A speculation — Sudden call activity in a takeover target before the announcement
- Sector rotation — Coordinated buying or selling across related tickers
- Event hedging — Institutional put buying ahead of macro events (FOMC, CPI releases)
The strongest signals combine multiple indicators: a sweep order, with a large premium, on an expiration that's near-term, with volume that dwarfs open interest.
What It Can't Tell You
Unusual activity isn't a crystal ball:
- Hedges look like bets. A large put purchase might be downside protection on an existing long stock position — not a bearish directional bet.
- Multi-leg strategies hide intent. One leg of a spread can look wildly bullish in isolation. Without seeing the other leg, you might misread the trade.
- Not every informed trade works. Even institutional traders are wrong regularly. Unusual activity indicates conviction, not certainty.
How to Filter the Noise
The challenge with unusual options activity isn't finding it — it's avoiding false positives. Here's what experienced flow traders focus on:
- Conviction stacking — Multiple unusual trades in the same ticker, same direction, within a few hours
- Premium threshold — Filter out small trades. $100K+ premiums carry more signal than $5K ones
- Sentiment confirmation — Trades bought at the ask (aggressive buying) are more meaningful than trades at the bid
- Context — Check if there's an upcoming catalyst (earnings, FDA decision, conference) that explains the activity
Robinflow's options flow scanner flags unusual options activity automatically using these criteria, scoring each trade so you can focus on the highest-conviction signals rather than scanning raw data manually. Combine this with dark pool analytics to see where institutions are positioning on the equity side.
