Investing in stocks can be a rewarding way to build wealth, but it's easy to make mistakes, especially if you're not aware of them. Here are some common stock investing mistakes that investors often make without realizing:

1. Lack of Research: Investing without thoroughly researching the company, its financial health, industry position, and future prospects can lead to poor investment decisions.
2. Emotional Investing: Making decisions based on emotions like fear and greed, rather than logic and analysis, can lead to buying high and selling low.
3. Overtrading: Excessive buying and selling can lead to high transaction costs and poor returns. It’s often better to adopt a long-term investment strategy.
4. Ignoring Diversification: Failing to diversify your portfolio can expose you to higher risk. Diversification helps in spreading risk across different assets.
5. Timing the Market: Attempting to time the market can be very difficult and often results in missed opportunities. Consistent investing over time usually yields better results.
6. Neglecting Fees and Taxes: Overlooking the impact of fees, commissions, and taxes on your investment returns can erode your profits significantly.
7. Chasing Performance: Investing in stocks that have recently performed well without understanding the reasons behind their performance can lead to poor future returns.
8. Ignoring Fundamentals: Focusing solely on stock price movements without considering the company's fundamentals, such as earnings, revenue growth, and debt levels, can lead to misguided investments.
9. Overconfidence: Being overly confident in your investing abilities can lead to taking unnecessary risks and making poor decisions.
10. Following the Herd: Investing based on what others are doing rather than your own research and analysis can lead to poor investment choices.
11. Lack of Patience: Expecting quick returns and not giving your investments time to grow can lead to frequent trading and suboptimal returns.
12. Ignoring Risk Management: Failing to set stop-loss orders or not having an exit strategy can lead to significant losses if the market moves against you.
13. Over-leveraging: Using too much borrowed money (margin) to invest can amplify losses as well as gains, leading to potential financial distress.
14. Ignoring Market Conditions: Not considering broader market and economic conditions can affect the performance of individual stocks and sectors.
15. Not Having a Clear Plan: Investing without a clear strategy, goals, and risk tolerance can lead to inconsistent and reactive decisions.

Awareness of these common mistakes can help you avoid them and improve your investing outcomes.