I was contemplating going long when a spike occured on the RUSSELL at 16:00 for a quick scalp (4:00pm ET) April, 28 2011.

What a memorable spike

Ya I saw that happen and was wondering if someone made a very expensive mistake, such as selling a block way above market?

kayaker 

Ya I saw that happen and was wondering if someone made a very expensive mistake, such as selling a block way above market?

Volume is typically spiking at 10:00 PM. I guess they are reporting block trades at the close of the underlying market.

But this not always accompanied by a price spike. The price spike shows a 1.1% range for the 1-minute bar closing at 10:00 PM.

Strange. Maybe somebody used a TIC order for the first time.

https://www.theice.com/publicdocs/futures_us/TIC_FAQ.pdf