While there is no one word answer to this question, it is influenced by a variety of factors. The ideal number of stocks that one must have in their portfolio is around 15-20. It's a lot easier to track these high-quality stocks than a large basket of 50 to 100 stocks because over-diversification lowers your returns while it doesn’t always reduce your risk. After you reach a certain number of stocks, the risk reduction benefit disappears and your expected returns also diminish. So, have limited stocks in your portfolio because you are not a mutual fund!