Real constituent weights
Published index weightings for major global benchmarks, refreshed and sanity-checked nightly.
Market movers
Not all indices are as diversified as they look. A handful of names drive most of the moves — this game asks you which ones, and by how much.
Concentration exposed
The top ten names in some benchmarks account for more than half the index.
Three close options
Answers are near enough that guessing rarely works — you need a feel for relative size.
Your index fund may be less diversified than you think
Buying a broad index is usually framed as buying the whole market. In practice, market-cap weighting means a small group of mega caps dominates the outcome, and a single sector can quietly become the majority of your risk. Knowing roughly what each giant weighs turns an abstract worry about concentration into a number you can actually reason about.
Frequently asked questions
What does the index weights game ask?
A weight is shown — say 5.9% of the Nasdaq-100 — and you pick which constituent carries it from three options.
Where do the weights come from?
Published index constituent data, validated nightly against concentration sanity checks before it reaches the question pool.
Which indices are covered?
Major benchmarks including the S&P 500, Nasdaq-100 and leading European indices.