In finance, a multi-factor model employs a set of different factors in its computations in order to analyze and explain market phenomena, as well as equilibrium prices of an asset. A multi-factor model can be used to analyze the returns of individual securities but also of entire portfolios.
A typical example is the famous Fama-French Three-factor model, an asset pricing model introduced back in the early 1990s by future Nobel prize laureate Eugene Fama and fellow researcher Kenneth French.
The two academics argued that the size and value factors capture a dimension of systematic risk that is not captured by market beta in the Capital Asset Pricing Model (CAPM). They proposed extending the CAPM, which resulted in their famous Three-factor model. This model was later extended with two additional factors: profitability and investment.