Currently, Volume of exchanges is only around 52 btc. Maybe Polo us waiting to see an increase in volume and then will list icn.
For Polo, Trade volume of 52 btc would be small.

Volume would increase as-
When ICN P and ICNX funds are launched, the demand of icn would increase, thus higher prices got icn. When prices would be higher, many will sell the icn. So trade volume is expected to increase in January.
I believe, if the reader volume exceeds 200 btc then it would definitely be listed on Polo'.

After all, Polo wants profits. If it starts trading now, it would earn less than 0.15 btc a day - very small amount for Polo.

If iconomi team said they have NDAs, then they have. I trust them.
If NDA was with a small exchange, then the exchange would have launched trading much earlier. Small exchanges normally launch trading earlier to earn small profits.
So it must be a NDA with a big exchange, looking for the best time to launch trading