Orders marked SWEEP are multi-exchange sweep to fill orders.
Orders marked SPLIT are single-exchange sweep to fill orders.

Intermarket Sweeps(sweep-to-fill) are smart routed orders that "sweep" multiple exchanges simultaneously to fill large orders quickly. They print to the tape as multiple smaller orders, yet they execute just microseconds apart. 

Because they show up as multiple small orders, they stay under everyone's radar. They're stealthy. When you add up all the smaller orders(they all originate from the same buyer), they often add up to major size.

Sweep orders are utilized when speed becomes paramount over the lowest possible price.

They are an indicator or urgency. As in, they indicate that the buyer wants to take a position in a hurry, which could imply that he or she is anticipating a large move in the underlying stock’s share price in the very near future.

FlowAlgo shows you the consolidated order data revealing the true size of these orders.
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