ES 12-15 vs ES 03-16

[jjanguda]

Hi,

I have a question about ES contract period.

I made a couple of ES trades today but
I found out that I traded ES 12-15 contract instead of 03-16.
Even though I traded on SIM, I had still no problem trading 12-15 contract.

I thought I wasn't able to trade 12-15 contract once it rolls over.
Why is 12-15 contract is still tradable and
For a day trader, what is a significant difference between 12-15 and 03-16 contract?

I see 03-16 is traded at least 3 times more than 12-15 (last time checked on CME site).
But 12-15 candlestick chart is more smoother (less pin reaction)

Appreciate any further explanation.
Thank you.

[NinjaTrader_Kyle]

Hello,

Thank you for writing in.

While traders typically roll over on the second Thursday of the expiration month the older contract does not actually expire until the following Friday leaving ES 12-15 tradeable up until 12/18/2015.

I hope that this helps to clear things up however if other questions come up which I could assist with please let me know.