In my opinion, this is the gretest factor which could affect the price of a particular ICO righ after listed on an exchange. Usually, the majority of bounty campaign participants never wanted to hold their coin for a long time because of FOMO that's why they choose to dump as soon as possible. Well, I can't blame them at all since I also have the same mindset.
On the contrary, low sales before the official start of the coin despite of having a crowdsale is another factor too. Imagine, what outcome do you expect if there are only few holders of that coin? Low price as well since there are only few circulating in the market.