Explanation

Return-generating models are specifically designed to estimate the expected return of a security. These models help investors understand what return they can anticipate from a particular security based on various factors.

Key Points:

1. Purpose of Return-Generating Models: These models (such as the Capital Asset Pricing Model - CAPM, Arbitrage Pricing Theory - APT, and multi-factor models) are used to estimate the expected return of individual securities or portfolios.

2. How They Work: Return-generating models typically relate a security's expected return to:

   • Risk-free rate
   • Market risk premium (for CAPM)
   • Multiple risk factors (for APT and multi-factor models)
   • Security-specific characteristics (like beta in CAPM)

3. Why Not the Other Options:

   • Option B: The expected return of the market portfolio is typically estimated using historical market returns or forward-looking estimates, not specifically through return-generating models.
   • Option C: The expected excess return on the market portfolio (market risk premium) is usually derived from historical data or surveys, not the primary output of return-generating models.

4. Example: In the CAPM formula: E(Ri) = Rf + βi × [E(Rm) - Rf], the model estimates E(Ri) - the expected return of security i.

Therefore, return-generating models are best used to estimate the expected return of a security, making Option A the correct answer.