Ethical Considerations in Client Investment Decisions

John, a portfolio manager, has been managing the investment portfolio of a high-net-worth client for several years. Recently, the client expressed a strong interest in investing in a new technology startup that has shown great potential. This startup is part of a sector that John believes is overhyped and carries significant risks. John is aware that his compensation could increase significantly if he recommends this startup, but he also understands that the client's interests should come first. Given this context, discuss the ethical considerations John should weigh when deciding how to proceed regarding the client's investment choice.