Type the formula for a cap-weighted index’s return, with new prices, old prices and share counts in named ranges.
Type the formula for a cap-weighted index’s return, with new prices, old prices and share counts in named ranges.
Answer
=SUMPRODUCT(prices1,shares)/SUMPRODUCT(prices0,shares)-1
Total capitalisation after over total before, minus one: 798,000,000 / 780,000,000 − 1 = 0.023077. For the price-weighted move use `=AVERAGE(prices1)/AVERAGE(prices0)-1`.
OpenStax, Introduction to Business (CC BY 4.0) §16.6–16.7 — shapes only; original three-stock index. The S&P/TSX Composite weighting is taught as register prose (spglobal.com methodology not reachable 2026-09-17).