The first reason is that the coin or token has no real value.
I agree with for first reason
And I do not agree with both of you, because the token at the beginning almost always has no value. Its value increases with the development of the project, and it always lasts at least a few months. It is rare for a project to collect money when it has a finished product that adds value to the project and his token.
even i dont agree ,sometimes its not always what you think, in my own opinion why price down after listing in exchanges its because investors wants immediate profit and then buy back at lower price, hold the coin for atleast month till the price recover.
This has certainly been the case in recent months, maybe even from around mid-2018. Earlier, in 2017, the situation was different, it was worth buying tokens at the ICO, because if the project was good, then often immediately after entering the exchange its price increased. At a time when a large number of scams appeared, investors began to leave the market and prices began to fall.
Most of the coins I know have a very good development plan, but when listed at big exchange, the value of that coin has only decreased and that makes me very nervous when choosing to invest. I think if this situation is not solved, investors will be very afraid to participate and will certainly affect their profits. In fact, I would love to invest in new projects but maybe I should consider carefully before making a decision.
Of course, this is a time for new projects but I will only choose to invest when the value of that coin is higher than the original price.
Like I wrote in the answer above, the situation now is different, but we always should to consider our investment on the basis of a good analysis of the project .. Although this sometimes does not help also.