Diversification All the Way Down

Layering diversification within signals, across factors, and across time produces a more robust multifactor equity portfolio than relying on any single style or timing model.

• The study combines cyclical value, enhanced value, momentum, and quality, while excluding size and low volatility because their betas would consume too much of the tracking-error budget.
• Enhanced value uses economic profit, intangible capital, and free cash flow, while momentum includes idiosyncratic momentum, short interest, hedge-fund positioning, analyst revisions, and economic-profit momentum.
• The US portfolio was tested against the STOXX US Universal Index from 2004 through May 2026, with quarterly rebalancing, a 1% ex ante tracking-error target, a 5% quarterly one-way turnover cap, and concentration and industry constraints.
• Over the full sample, the combined portfolio had an information ratio of 1.00, versus 0.94 for enhanced value, 0.73 for quality, 0.65 for momentum, and -0.20 for cyclical value.
• A timing overlay combining three bounded models improved results over the most recent three years but added little over the full sample, supporting only modest tactical tilts.

Takeaway: Investors should diversify signals within each factor and combine imperfectly correlated value, momentum, and quality exposures; factor timing may be a small enhancement, but the evidence does not justify replacing a diversified core with forecasts.