"Loose cannon" trade

[TedLincoln]

Here is the attachment

[TedLincoln]

Each day I see a trade in the SPY that seems to be completely oddball. A trade will take place a long distance away from the bid and ask in the market, after which the market returns to normal. My attachment illustrates this. Is someone pulling shenanigans in the SPY market, or what?

[ctrlbrk]

It is bad tick data.

IQfeed had this problem non-stop. Zen Fire doesn't (I've never seen it).

You can ask your provider to clear up the trades, but in my case, back when I had IQfeed, it was a lost cause.