These are big whales, some big trading investment firms, which are responsible for these dump and pump. I never tried to sell any of my coins as just want to hold them when they trying to dump or pump the coin.
Are you sure they are responsible for the dump and pump? I think there are other people who have influence on dumps and pumps, especially the big investors who are not rich people who may not be associated with any team and institution, not to mention there are some traders who, although the impact may be small but still worth counting