The capital asset pricing model (CAPM) approximates return as a linear function of beta.

FORBES: The Efficient Frontier

The "capital asset pricing model" identified one factor, beta, or a stock's volatility relative to the index, as pivotal to the stock's returns.

WSJ: Supercharging Your Investment Portfolio

This mathematical approach to investing led to the famed Capital Asset Pricing Model by Sharpe, Lintner, and Black, the Option Pricing Model by Black and Scholes, and other important theories.

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The Efficient Market Model does not suggest that any particular model of valuation such as the Capital Asset Pricing Model fully accounts for risk and uncertainty or that we should rely on it to predict security returns.

WSJ: Book Review: Models Behaving Badly

And then it hit me: the asset allocators, those exact folks who seem to be turning their backs on VC today, are the ones who bow at the altar of CAPM, the Capital Asset Pricing Model.

FORBES: A Dollar And A Dream: Making The Case For Venture Capital

Even though it spits out percentages to several decimal points, the capital-asset pricing model, as the conceptual framework for calculating the rates is called, is controversial in itself.

ECONOMIST: Corporate finance