Cliff Asness on Market Bubbles and Quant Investing Today Legendary quant investor Cliff Asness urges caution when labeling markets as bubbles, emphasizing that true bubbles require extreme conditions and remain difficult to identify in real time. While technology company concentration dominates indices, Asness notes this matters far less for diversified systematic strategies that can take both long and short positions across broad stock universes. He views the 2022 breakdown in stock-bond correlation as unusual rather than structural, caused by rare inflation shocks. Asness argues the traditional 60/40 portfolio deserves realistic expectations: the 40% bond allocation primarily deleverage stocks rather than truly diversify against equity risk.