The Little Book Of Common Sense Investing
What you will learn
Explain why diversification, recurring costs and market risk matter in an index-fund approach.
Read and apply
Read the The Little Book Of Common Sense Investing book page (opens in a new tab)
On the book page, choose one idea relevant to the objective above. Write what evidence would support it and what could weaken it. Then complete the filing or source activity below and return to these course questions.
Check your understanding
Choose an answer, then open the feedback.
Which approach does Bogle argue is a practical starting point for many investors?
A. Trade frequently to catch every move. B. Hold a broad, low-cost index fund for the long term. C. Choose funds only by last year’s return.Show answer and feedback
B. Broad diversification and low costs are central ideas in this book; an index fund still carries market risk.
Why do fund expenses matter?
A. They reduce the return an investor keeps. B. They remove all market risk. C. They guarantee a higher return.Show answer and feedback
A. Costs reduce net returns, and a recurring difference can compound over a long holding period.
What should you check before treating a past fund winner as a future winner?
A. Only the latest ranking. B. Whether its manager promises a gain. C. Costs, diversification, risk and the limits of past performance.Show answer and feedback
C. Past performance does not establish what will happen next; compare the fund’s structure and risks.
Why question: Why might a small annual cost difference matter over many years?
Show a sample explanation
A lower net return leaves less money to compound in later years. The effect depends on actual returns, fees, taxes and time invested.
Try the book’s cost lesson
Open the calculator with $10,000, 20 years and a 7% assumed return. It shows about $40,387. Change only the rate to 6% and record the new projection of about $33,102. The $7,285 difference illustrates one percentage point of lower net return; the calculator does not deduct fees or predict investment results.
Key takeaways
- Broad diversification and low costs are central ideas in this book; an index fund still carries market risk.
- Costs reduce net returns, and a recurring difference can compound over a long holding period.
- Past performance does not establish what will happen next; compare the fund's structure and risks.
This activity is for financial education. An example or book framework does not guarantee investment results.
AI responses are for educational purposes. Always verify with official course materials.
This lesson teaches a concept. It is general education, not advice about your money. Before you act on anything you learn here, speak to someone licensed.
Sources and reference material
Primary sources and original reference material for the concepts discussed on this page.
- SEC Investor.gov: Asset Allocation, Diversification, and Rebalancing
- FINRA: Asset Allocation and Diversification
References added 14 October 2026.
AI responses are for educational purposes. Always verify with official course materials.
This lesson teaches a concept. It is general education, not advice about your money. Before you act on anything you learn here, speak to someone licensed.
This lesson teaches a concept. It is general education, not advice about your money. Before you act on anything you learn here, speak to someone licensed.
