Globex Euro-Dollar Futures Options in IB

Why are there two different Expirys for one month?

For example MAR 14 '08 and MAR 17 '08. The MAR 14 one looks like it has more bids.

 

These are most likely mid-curve options. IB lists them as GE1, GE3, etc.

 

Yes, I noticed the MAR 14 one displays under GE0, but may I ask what is a mid-curve option?

 

They are short term options on the red, green, and gold contracts.

So, you could buy a June '08 red mid-curve call. While the option expires in June '08, the futures contract it uses as an underlying is the June '09. IB's symbol for these is GE0, I think.

This is a great source of information on these mid-curves:
http://chicagomercantileexchange.net/files/3DEurodollarTrades.pdf

 

Thanks! Nice graphics.