SP3O

Here's another weird SP3 trading story.

A few days ago I set an opportunistic SP3O buy for 50,000 at 12 cents per option (half a cent under the 12 month low). A day later someone else placed an SP3O buy for 60,000 at 12.5 cents. Well today on the open, someone sold 100,000 SP3O at 12 cents per option, thus foregoing $300 from the buyer of 60 000 at 12.5 cents, and cleaning up 40,000 of my own 50,000 buy order

I'm certainly not complaining about acquiring 40,000 SP3O at 12 cents per option, and doubtless the other buyer is even less likely to be complaining, but I can't understand why a seller would liquidate 100,000 options for $300 less than if the sale was done "at market".

Maybe someone a bit cleverer than me can suggest where the logic lies in the seller's actions?

zeno9