Insider trading: this is formally forbidden and punished in regular markets by stock exchanges organisations, but since crypto markets are unregulated, there is no way to apply any control here. Insider trading is when you have insider information about a project before anyone else or before the news hits the public, and you can thus acquire or sell a lot of cryptocurrency before the news break, allowing you to make huge profits, or to minimalise your losses.
Portfolio managers are professionals who invest portfolios, or collections of securities, for clients. These managers get recommendations from analysts and make the buy or sell decisions for the portfolio. Mutual fund companies, hedge funds, and pension plans use portfolio managers to make decisions and set the investment strategies for the money they hold.
Since the underlying businesses operate in differing markets, sectors and countries, their quoted prices move independently as supply and demand in them rises and falls and new information is released to the public about the current business situation. It is the changing of prices that offer investors the opportunity to make a capital gain (or loss) via ownership.