Steven Cohen of Point72 Asset Management just trimmed his Amazon stake and initiated a position in Apple.Investment firms managing over $100 million in stocks are required to file a form 13F with the Securities and Exchange Commission (SEC) once quarterly. These filings can be helpful as they provide a glimpse into what the companies' sophisticated investors, such as hedge fund managers, are buying and selling.One investor I enjoy following is Steven Cohen of Point72 Asset Management. Last quarter, Point72 ...