Bogleheads On Investing Podcast · bogleheads

Episode 68: Rolf Agather on investment index methodology and innovation, host Rick Ferri

·54 min·3 clips

Russell moved from a 3,000-stock universe to size, value, and growth benchmarks for active managers.

1. Bogleheads On Investing Episode 68 centers on indexes, index evolution, and index funds. 2. Rick Ferri hosts, and Rolf Agather, Morningstar’s head of index research and products, brings 40 years of index work at Russell, FTSE, FactSet, and Morningstar. 3. The episode asks what makes a good index and why index methodology matters now that 53% of mutual-fund money is indexed. 4. Ferri and Agather begin with the Dow Jones Industrial Average, created in 1896 by Charles Dow as a price-weighted market indicator with 12 stocks. 5. Agather says Charles Dow calculated the index on pencil and paper and used prices from the New York Stock Exchange. 6. They contrast the Dow’s price-weighted design with the S&P 500’s 1957 launch as a capitalization-weighted, broader U.S. market measure. 7. Ferri notes that the S&P 500 later became an economic indicator and entered the leading indicators index. 8. Agather describes Russell’s 1984 launch of the Russell 3000 and the later Russell 1000, Russell 2000, value, and growth indexes. 9. He says Russell built those benchmarks to match manager research and to benchmark large-cap and small-cap active managers more fairly. 10. Ferri lists benchmark principles from Larry Siegel’s Benchmarks and Investment Management, including simplicity, relevance, comprehensiveness, replicability, stability, no barriers to entry, and expense awareness. 11. Agather says rules-based means the rules are published in advance and contain little or no discretion. 12. He links that structure to a passive alternative that investors can use when they do not want active-management fees or uncertainty. 13. Ferri and Agather discuss Russell’s annual reconstitution cycle and the front-running risk that came from advance knowledge of index changes. 14. Agather says one response was migration and phase-ins, which slowed turnover and reduced market impact. 15. He adds that banding and buffering also helped keep companies near breakpoints from being moved wholesale all at once. 16. Ferri raises growth and value classification, and Agather says Morningstar uses five characteristics for value and five for growth rather than Russell’s single price-to-book factor. 17. Agather says Morningstar’s core category helps capture the middle of the style spectrum that pure growth and pure value labels miss. 18. The interview is conversational and technical, with Ferri steering through history, methodology, and practical consequences for index funds. 19. Listeners interested in index funds, benchmark design, and active-versus-passive comparison will get the most from this episode. 20. Listeners looking for market commentary or a stock-picking debate may skip it.

As heard by us

A careful look at how index rules shape the way passive investing works.

Indexes usually sit in the background, but this episode treats them as the frame that modern investing hangs on. It walks through how indexes are built, why the rules change, and how rebalancing, reconstitution, and the growth-value split affect tracking and turnover.

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If you want the mechanics behind index funds, this is the cleanest kind of deep dive.

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