Robert Arnott Discusses the Process Behind Research Affiliates

Episode Summary

Executive Summary: Barry Ritholtz interviews Rob Arnott of Research Affiliates about fundamental indexing, factor investing, valuation, and bubbles. Arnott argues that cap-weighted indexing embeds momentum and overweights expensive winners, while fundamental indexing systematically buys cheap stocks and trims expensive ones. He also explains why many “smart beta” claims are overstated, why bubbles can be objectively identified, and how valuation and rebalancing drive long-run returns.

Main Topics: Fundamental indexing vs. cap-weighted indexing (Priority: 5/5): Arnott explains Research Affiliates’ model: licensing index ideas rather than directly managing most assets, and why fundamental indexing is built on economic measures like sales, earnings, book value, and dividends rather than market price. Smart beta and factor investing (Priority: 5/5): The conversation distinguishes genuine factor effects from data mining, notes that hundreds of factors have been published, and emphasizes that not all factor strategies are durable or investable. Valuation, mean reversion, and contrarian discipline (Priority: 5/5): Arnott argues that cheap stocks outperform because of rebalancing and mean reversion, not magic. He frames value investing as a behavioral contrarian strategy that buys what is unloved and trims what is adored. Bubbles, anti-bubbles, and concentration risk (Priority: 4/5): The discussion examines how to define bubbles objectively, how anti-bubbles emerge when sectors are priced for disaster, and why large-cap dominance can be misleading and unstable. Index inclusion effects and market impact (Priority: 4/5): Arnott cites evidence that S&P 500 additions and deletions create large performance gaps due to front-running, valuation differences, and the market impact of index reconstitution. Capacity, implementation, and business model (Priority: 3/5): Research Affiliates’ licensing model is presented as scalable and low-turnover, with Arnott arguing it avoids the operational burdens of direct trading while preserving capacity. Personal background, influences, and reading (Priority: 2/5): Arnott shares mentors, books, hobbies, and his philosophy that work should be fun, revealing a lighter side behind his quantitative reputation.

Key Arguments: Fundamental indexing works because it breaks the link with price and rebalances toward economic footprint, creating a structural sell-high/buy-low discipline. Cap-weighted portfolios overallocate to stocks that have already become expensive and underweight undervalued names, which embeds a momentum tilt that can reverse. Many published factors are likely the product of data mining; the challenge is separating durable return drivers from historical accidents. Value outperforms over the long run largely because it is uncomfortable and cyclical; periods of underperformance are what make the eventual premium possible. The real source of alpha in many value strategies is rebalancing/mean reversion rather than simply being “cheap.” S&P 500 additions and deletions are not neutral events: additions tend to be expensive and deletions cheap, and the announcement/implementation window allows front-running. Bubbles can be defined objectively by requiring extreme assumptions to justify prices and by looking for buyers who expect to sell to a greater fool. The largest companies in the world often fall out of the top ranks within a decade, showing that market-cap leadership is unstable and that concentration carries hidden risk. Fundamental indexing has high capacity because it trades broad, diversified names and uses low-turnover rebalancing, unlike niche factor strategies that depend on illiquid securities. Valuation matters for factors just as much as it does for individual stocks; chasing a strategy after it has become expensive can lead to disappointing future returns.

Data Points: Assets managed/licensed through Research Affiliates strategies: over $200 billion - Scale of RA-linked strategies discussed in the interview Directly managed assets at Research Affiliates: 5% of assets under 'management' in 2014 - Arnott says RA stopped directly managing money because it was a small part of the business but drove complications Revenue share from directly managed assets: 15% of revenues - One reason RA exited direct management Fundamental index launch timeline: 2003-2005 - Idea conceived in 2003, formalized by mid-2004, first fund launched in 2005 Published factor count: over 500 factors - Arnott warns many published factors may be data-mined Year of paper 'How Can Smart Beta Go Horribly Wrong?': a couple of years ago (relative to interview) - Used to illustrate valuation/multiple risk in factor strategies S&P 500 add vs. delete performance gap: 23 percentage points - Stocks added to the S&P 500 underperformed deletions by this amount over the subsequent 12 months from 1989-2017 Performance during reconstitution grace period: nearly 9% - Added stocks outperformed discretionary deletions during the announcement-to-effective-date window Share of S&P discretionary adds trading at premium multiples: over 90% - Arnott argues additions are generally expensive Share of S&P discretionary deletes trading at discount multiples: over 90% - Arnott argues deletions are generally cheap Average valuation multiple gap between adds and deletes: more than 3:1 - Adds are much more expensive than deletions on average Value/growth valuation gap in 2000: 8:1 - Arnott says value was profoundly cheap relative to growth at the dot-com peak Value/growth valuation gap in 2007: 2.5:1 - He says value became relatively expensive before the quant crash Emerging markets deep value valuation: 2 to 3 times cash flow - Example of an anti-bubble in early 2016 RAFI emerging markets Shiller P/E: below 6 - Illustrates how cheap fundamental index exposure briefly got in emerging markets Top 10 global market-cap companies persistence: only 2 of 10 remain 10 years later on average - Used to show instability of market-cap leadership Research Affiliates movie watching hobby: over 1,500 movies in 6 years - Arnott describes his personal interests Audrey Hepburn age at death: 63 - Mentioned during a discussion of classic films Salomon Brothers tenure: 14 months - Arnott cites an early career failure and what he learned from it Fundamental index turnover: 10% to 15% annually - For FTSE-RAFI and related staggered rebalancing approaches BlackRock RAFI assets: over $10 billion - BlackRock is described as a licensee/affiliate running RAFI strategies

Pivotal Quotes: "The arithmetic of active investing." — Barry Ritholtz / Rob Arnott reference: Discussion of Bill Sharpe’s framework for why active managers collectively must underperform after costs "How can smart beta go horribly wrong?" — Rob Arnott: Arnott describes his controversial paper warning that factor strategies can be hurt by valuation expansion and mean reversion "Yes, it’s a bubble, so what?" — Rob Arnott: Arnott explains his paper arguing that bubbles should be defined objectively and not merely noted by intuition

Implications: Listeners should view index and factor strategies through the lens of valuation, rebalancing, and capacity, not marketing labels. The interview suggests many popular strategies can disappoint if bought after becoming crowded or expensive.