Options Sweeps vs Blocks: Understanding Unusual Options Flow

Learn options sweeps vs blocks, how unusual options flow works, key data points to check, and how an options flow scanner can simplify flow analysis.

In the options market, thousands of contracts may be traded during one trading session. The majority of these transactions are ordinary, while a smaller number attract attention due to their size, premium, odd volume, method of execution, or the way they are concentrated around a specific strike price and expiration date. This kind of activity is generally referred to as unusual options flow and can provide traders with an additional source of information when they are studying a stock. When talking about this activity, two terms come up often: options sweeps and options block trades . Even though both may involve large transactions, they are not the same. A sweep is usually connected with an order aiming to be executed against the available liquidity, whereas a block is a big transaction or print which may indicate a substantial amount being executed in a more concentrated way. It is useful to understand the difference between options sweeps and blocks since the figure given in the headline usually does not give the whole picture. Although a $1 million options trade may appear impressive, traders still have to find out whether it was a buy or a sale, where it traded in relation to the bid and ask prices, how much open interest was already present, and what the underlying stock was doing at that time. It follows that the aim of options flow analysis should be to carry out investigation, not prediction; although it can point out activities that are worth looking into, it does not automatically show the trader's full strategy or ensure what the underlying stock will do next. What Is Unusual Options Flow? The term unusual options activity describes trading activity in an option which stands out when compared with the usual level of activity for a particular contract, stock, or the wider market. Since there is no single, universally accepted definition, a trade can draw attention for having an unusually high premium, an unusually high volume, a large number of contracts, aggressive execution, or for being of a size relative to the existing open interest. The importance of this distinction lies in the fact that raw options volume and options flow are not the same. Volume indicates the number of contracts traded over a given period, while flow analysis tries to provide some context for those transactions, such as the execution price, the characteristics of the contract, the size of the trade, and whether the activity is concentrated or unusual. Open interest is another important element in the puzzle. According to the Options Industry Council, volume refers to the level of trading activity in a session, whereas open interest relates to the contracts that remain open. The fact that a contract is traded 20,000 times does not necessarily mean that 20,000 new positions have been created. Why Large Options Transactions Attract Attention Large transactions may draw attention since institutions, funds, market makers, and other sophisticated participants are a