EDIT:
oh, nice.. that was helpful and pretty much what I was looking for.. thanks for sharing
Hey
That might be helpful for you to understand the reason behind it - http://cryptoandblockchaintalk.com/why-do-prices-drop-when-an-ico-ends-27
Take care!
The first reason it could be that people dump their airdrops and bounties. However, frequently, they are quite delayed and I doubt that's kind of a big issue.
Secondly, why people who just bought will sell at a loss straight after the ICO. It could be because they found something dodgy about the project or price is falling and they decided to exit with others.
The last reason I can think of is that those who bought as early birds or private investors, who have some profit may sell it with some profit...Anyways, those all factors may impact, as well as a bear market.