Understanding Stock Market Indices
A plain-English guide to what indices like the S&P 500, Nasdaq and Dow actually measure, how they are built, and how ordinary investors put money behind them.
- 1Part 1 of 9 11 min
What Is a Stock Market Index? A Plain-English Guide
A beginner-friendly but thorough explanation of what stock market indices actually measure, why they exist, who runs them, and how they differ from the funds that track them.
Read part 1 - 2Part 2 of 9 13 min
The S&P 500 Explained: Inside America's Flagship Index
A thorough beginner's guide to the S&P 500 — how its 500 companies are chosen, how float-adjusted market-cap weighting works, what the sector breakdown looks like in 2026, and why a handful of mega-caps now dominate the index.
Read part 2 - 3Part 3 of 9 12 min
Nasdaq Composite vs Nasdaq-100: Untangling the Two 'Nasdaqs'
Beginners constantly confuse the Nasdaq Composite with the Nasdaq-100. This guide explains exactly how the two differ, why 'the Nasdaq' usually means the 100, the index's tech-growth tilt, and how its rebalancing works in 2026.
Read part 3 - 4Part 4 of 9 12 min
The Dow Jones Industrial Average: The Famous Index That Works Differently
The Dow is the most famous market index and the most misunderstood. This guide explains its 30-stock structure, the unusual price-weighting that makes a high-priced stock dominate, the Dow Divisor, its 130-year history, and why professionals prefer the S&P 500.
Read part 4 - 5Part 5 of 9 12 min
Beyond the Big Three: A Tour of the World's Other Major Stock Indices
The S&P 500, Nasdaq, and Dow are not the only indices worth knowing. This guide maps the wider landscape — U.S. small-caps and total-market indices, plus the major international benchmarks of the UK, Germany, Japan, Hong Kong, and Europe — and explains what each one signals.
Read part 5 - 6Part 6 of 9 12 min
How Stock Indices Are Calculated: Weighting Methods Made Intuitive
The weighting method behind an index quietly determines everything it tells you. This guide explains price weighting, market-cap weighting, float adjustment, and equal weighting with a simple worked example, and shows how the choice produces dramatically different results — including the 2026 gap between the standard and equal-weight S&P 500.
Read part 6 - 7Part 7 of 9 13 min
How to Actually Invest in an Index: Index Funds and ETFs Explained
You cannot buy an index directly — so how do people invest in the S&P 500? This guide explains index funds versus ETFs, expense ratios and how they compound, tracking error, and walks through the real 2026 numbers for SPY, VOO, IVV, and QQQ.
Read part 7 - 8Part 8 of 9 11 min
How to Read Index Movements: Points, Percentages, and What Actually Moves the Market
Why a 200-point Dow move can be trivial, why points mislead and percentages tell the truth, what actually drives an index on a given day, and why the index can rise while your portfolio falls. A practical literacy guide using real June 2026 examples.
Read part 8 - 9Part 9 of 9 12 min
The Limits of Indices: Concentration Risk and Common Misconceptions
Indices are powerful but not the full story. This closing guide covers the record mega-cap concentration of the 2026 S&P 500, why an index isn't the whole economy, survivorship and reconstitution bias, the real meaning of past-performance caveats, and what indices simply cannot tell you.
Read part 9