“Stapleton then begins a description of factor-based strategies. These include common equity factors, such as value, size, and quality, and they can be used either in place of or to complement market-cap-weighted indexing. She points out that relative to market-cap weighting, factor-based strategies tend to diversify risk exposures; are transparent in terms of factor selection, weighting, and rebalancing; but can be copied by other investors, which can reduce the advantages of a strategy.”
Stapleton’s comment is incorrect regarding risk exposure. Relative to broad-market-cap-weighting, passive factor-based strategies tend to concentrate risk exposures, leaving investors exposed during periods when a chosen risk factor is out of favor.
If a factor based model has multiple factors (size,value,momentum), won’t that provide diversification as opposed to broad market cap weighted?