Block trade (options block order)

A block trade is a single large options print that fills all at once, typically negotiated off-exchange between two counterparties or matched against a large resting institutional order, rather than sliced across multiple venues the way a sweep is. The defining feature is the execution: one large fill, one timestamp, one print, as opposed to a sweep's signature of many smaller fills landing across several exchanges within the same instant.

Because a block often reflects a negotiated trade between two parties who already agreed on price and size before it printed, it can represent either urgency or the opposite: a large fund quietly putting on or unwinding a position at a price both sides were comfortable with, with no particular rush behind it. That's a meaningful difference from a sweep, where urgency is closer to a defining feature of the execution style itself. A block's signal depends heavily on context. The strike, expiry, and how it compares to the stock's typical options volume all matter more than the fact that it was a block at all.

A block trade doesn't reveal which side initiated it. A resting institutional sell order getting filled by an aggressive buyer looks identical in the tape to a large fund quietly building a position through a negotiated print. It also doesn't say whether the trade is a standalone directional bet or one leg of a larger hedge, spread, or portfolio rebalance that only makes sense alongside other positions the counterparty holds elsewhere. Size alone, without that context, isn't conviction. Two blocks of identical size in the same name on the same day can mean completely different things once you factor in which strikes and expiries they hit, and whether they cluster with other unusual activity or stand alone.

Consider a single block trade of 5,000 call contracts in a large-cap name, all filling at once at a single strike and expiry with no other unusual prints in that name that day. That's a meaningfully different picture from the same 5,000 contracts arriving as forty separate sweeps across the session. Same total size, but the block suggests one counterparty decision executed at one moment, while the sweep pattern suggests either a single urgent buyer or a slower accumulation by several participants, each worth reading differently even though the aggregate notional ends up the same.