Part 27 of 43 in How to Invest Your Money: Lessons from the World’s Greatest Investors, Adapted for the Indian Investor← Part 26Part 28 →
This chapter explains how investors can improve by reviewing their own buying and selling decisions. It helps readers build better investing rules, recognize recurring strengths and mistakes, and keep learning from reliable sources.
- Keep a simple record of major buys, sells, and the reasons behind them.
- Review results yearly to see which investment ideas worked, which failed, and whether you followed your process.
- Use recurring patterns to refine your circle of competence, rules, and checklists.
- Small improvements in process quality can produce large differences in results over decades.
- Read annual reports, business journalism, investor letters, and books, using AI to connect ideas more quickly.
The best feedback comes from your own decisions. Maintain a simple log of major buys, sells, and the reasons at the time. Once a year, review outcomes without self-justification. Which theses proved correct? Which failed, and why? Did you follow your process or override it? Patterns will appear—perhaps you are skilled at identifying quality compounders but poor at timing, or perhaps you consistently underestimate competitive risks in certain industries.
Use these insights to refine your circle of competence and your rules. You may decide to outsource more decisions to index funds, to narrow the types of businesses you analyze, or to add a specific checklist item that would have prevented a past mistake. This iterative improvement is itself a form of compounding. Small gains in process quality, sustained over decades, produce large differences in results.
Reading remains essential. Annual reports, high-quality business journalism, investor letters from respected managers, and books on business history and psychology all expand the set of mental models available to you. AI can help you extract and connect ideas from these sources more quickly, but the act of engaging with primary material builds deeper understanding.
Frequently asked questions
How can I learn from my investment mistakes?
Keep a log of major buys and sells, then review the outcomes once a year without self-justification. Identify which ideas failed, why they failed, and whether you followed your process.
What should I include in an investment decision log?
Record major buys, sells, and the reasons for each decision at the time.
How can I improve my investing process over time?
Look for repeated patterns in your results and use them to refine your circle of competence, rules, and checklists. You might analyze fewer types of businesses, use more index funds, or add a checklist item to prevent a past mistake.
What should investors read to keep learning?
Annual reports, high-quality business journalism, investor letters from respected managers, and books on business history and psychology can expand your mental models. AI can help extract and connect ideas, but engaging with primary material builds deeper understanding.