$SPDR S&P 500 ETF (SPY.US)$ any idea why someone would do th...

HashiraOP :

Rina888 : What do you mean? Do what ?

HashiraOP :

HashiraOP : below snapshot

HashiraOP : there is a sell order highlighted for 251k shares at 425 when spy was at 430

HashiraOP : is it some sort of backfill in the book?

Cow Moo-ney : My guess is options get exercised