When a large options order hits the tape, one of the first things we look at is how it was executed. The two labels you'll see most — sweep and block — don't describe what was bought; they describe the mechanics of the fill. And that reveals a lot about the trader's urgency and intent.
What is a sweep?
A sweep is a single large order that gets split and filled across multiple exchanges at once — "sweeping up" all the available contracts at each price level until the whole order is filled, instantly. The trader is prioritizing speed over price. They want the position now, and they're willing to pay up — climbing through the offers across venues — rather than wait. That urgency is exactly why sweeps catch our attention.
Example: A trader wants 5,000 call contracts, but no single exchange is showing that much at one price. The order fires across six exchanges simultaneously — 800 here, 1,200 there, 1,500 somewhere else — filling all 5,000 in milliseconds, paying slightly higher as it lifts each offer. On our cards this shows as SWEEP, often filled at or above the ask.
Reads as: urgency. Someone needed this position immediately — frequently shorter-term, time-sensitive conviction.
What is a block?
A block is a single, large trade negotiated and printed as one lot — usually arranged privately (off-exchange or through a broker/dark pool) between institutions, then reported as one big print. Here the trader is prioritizing size and discretion over speed. They want to move a huge position at an agreed price without tipping off the market or pushing the price against themselves. So instead of sweeping, they negotiate one clean fill.
Example: A fund wants 10,000 contracts. Sweeping that through the open market would move the price and signal their hand. Instead they arrange a single block at a negotiated price — printed as one 10,000-lot, often at the midpoint or a set price. On our cards this shows as BLOCK.
Reads as: deliberate, institutional positioning. A big, considered bet — and often a longer time horizon.
Sweep vs. block — side by side
| Sweep | Block | |
|---|---|---|
| Execution | Split across many exchanges | One negotiated lot |
| Priority | Speed & urgency | Size & discretion |
| Where | Multiple lit exchanges | Often off-exchange / dark pool |
| Fill price | Often at or above the ask | Often at the midpoint / negotiated |
| Reads as | Urgent, time-sensitive | Deliberate, institutional |
| Typical horizon | Shorter-term | Can be longer-term |
How we use it
Neither label is automatically bullish or bearish — direction comes from the contract and the fill. But the style tells you something real: a sweep flags urgency (someone in a hurry, willing to pay up), while a block flags size and intent (a large, deliberate position). We weight aggressive sweeps into low open interest heavily as conviction signals, and we watch big blocks for institutional positioning.
Research and education only. Not financial advice, and not a recommendation to buy or sell any security.