The difference between large and small investors lies in the amount of money they invest in the project, the income from a successful investment also distinguishes them.
If we talk about investors who invest in the project at the ICO stage, the differences may not always be (except for the amount of the invest). I am a small investor. I do not know how they choose objects for investment, but there are suggestions that they do it differently than small investors.
The market allocates investors, of course, not only in terms of investment. Although they have one goal, they act in completely different ways.
Now wery often more profitable to buy tokens after the ICO whey they will appear on cryptoexhanges. Some tokens are not listed at exchanges besides DEX and it is very hard to sell them.