Market concepts

Unusual options activity, explained.

4 min read · Updated Oct 11, 2026 · Education only

“Unusual options activity” is one of the most searched phrases in options trading. Screens of large trades, sweeps and blocks are everywhere. The idea is simple: when far more contracts trade than usual, someone may know something or feel strongly about a move. The reality is more complicated, and understanding why will help you read this kind of data sensibly.

What “unusual” means

Options activity is usually called unusual when trading in a specific contract, or across a stock's options, is far above its normal level. Common ways to measure it include:

• Volume vs. average volume: a contract that normally trades 300 times a day suddenly trades 6,000 times.
• Volume vs. open interest: today's volume is larger than the number of contracts that were open before the day started, which suggests at least some new positions.
• Size and premium: a single order for thousands of contracts, or a large dollar amount of premium, stands out.
• Short-dated, out-of-the-money focus: heavy buying of cheap contracts that need a big move soon draws attention.

There is no single official definition. Different screens use different thresholds, which is why the same day can look “unusual” on one platform and normal on another.

Volume vs. open interest

These two numbers are the backbone of any activity reading, and they are often confused.

Because open interest only updates overnight, you cannot tell during the day whether a big trade opened a new position or closed an old one. The next morning's open interest change offers a clue, but it nets together everyone's activity in that contract, not just one trade.

Sweeps, blocks and where a trade printed

Activity screens often label trades by type. A block is a single large trade, often negotiated. A sweep is an order split across several exchanges at once to fill quickly, which some read as urgency. Screens also note whether a trade printed near the ask (suggesting a buyer was more aggressive) or near the bid (suggesting a seller was). These are useful hints, but they are inferences, not facts about intent.

Why big trades are often not bets

The biggest limitation of following unusual activity is that the trade you see is rarely the whole story. A large order might be:

• A hedge. A fund holding millions of dollars of stock may buy puts as insurance. That says nothing about expecting a fall.
• One leg of a spread. The visible call purchase may be paired with a call sale at another strike, which changes the meaning completely.
• A roll or a close. A trader moving an existing position to a later expiration creates large volume without a new view.
• Part of a stock trade. Options are often traded together with shares, for example in covered calls or collars.
• Market-maker activity. Dealers trade constantly to manage their own inventory.

Even when a trade really is a directional bet, the trader may be wrong, may have a different time horizon, or may be risking a tiny fraction of a much larger portfolio.

Events change what “normal” looks like

Activity tends to cluster around scheduled events: earnings reports, product launches, Federal Reserve announcements and index rebalances. Heavy trading before an earnings report is expected, not unusual. Implied volatility also tends to rise before such events and fall afterward, which affects option prices regardless of direction. Our guide to implied volatility and IV crush explains why.

Using activity data sensibly

Treated as one input among many, activity data can be useful. Some questions worth asking when a contract shows unusual volume:

1. Is there a scheduled event before expiration that explains the interest?
2. Did volume exceed open interest, and did open interest change the next day?
3. Did trades print near the bid or the ask, and was there matching activity at nearby strikes (a possible spread)?
4. How liquid is the contract? Wide bid/ask spreads make any position expensive to enter and exit.
5. What would have to happen, and by when, for the contract to be worth more than its price?

Where this fits in the app

The Stocks and Options Alerts app shows unusual volume on its Market Trends screen and lets you filter the alerts feed by type, including volume. These are information to research, the same for every user, and not instructions to trade. Every alert the app publishes is tracked to a close, and the last 200 closed alerts are listed on our Results page, wins and losses alike. You can read more on how the app works.

The bottom line

Unusual options activity tells you that interest in a contract is higher than normal. It does not tell you who traded, why, or what happens next. Read it as a prompt for questions, not as an answer, and remember that options can lose their entire value. See our Risk Disclaimer.