Diversification, in its true sense, is not about how many assets you own. It is about how many independent outcomes you are exposed to.
A well-diversified portfolio is one where your sources of return are not dependent on the same driver. Different cash flows. Different risks. Different economic sensitivities. You are not just spreading money, you are spreading uncertainty.
For example, owning five banking stocks is not diversification. You may have five names, but you have one underlying risk. The same is true for holding multiple consumer stocks, or even different assets that all react the same way to interest rates, inflation, or currency movement.
True diversification asks a deeper question:
If one part of my portfolio fails, does another part still stand strong for a completely different reason?