My opinion on what is happening is that certain naive individuals expected a significant increase in the AMP price immediately after the crowdsale concluded. When they realized that it might not occur immediately they all started panic selling causing this decline and are pointing their fingers at imaginary "whales" when in reality they should be looking in the mirror and pointing it at themselves.
There was no manipulation ? how about the large sell walls followed by bots on the sell side driving the price down ? it was obvious market manipulation.
If you dont see it you're a rookie trader or part of the manipulation team.