On the sensitivity of the Black capital asset pricing model to the market portfolio
Titel:
On the sensitivity of the Black capital asset pricing model to the market portfolio
Auteur:
Buckley, Winston S. Harris, Oneil Perera, Sandun
Verschenen in:
Risk and decision analysis
Paginering:
Jaargang 4 (2013) nr. 3 pagina's 177-189
Jaar:
2013-08-12
Inhoud:
We show that Black Capital Asset Pricing Model (Black CAPM) is extremely sensitive to the choice of the market portfolio and becomes unstable as market portfolios approach the Global Minimum-Variance portfolio. When market portfolios approach the minimum-variance portfolio, the expected return on the zero beta asset approaches negative infinity and its variance increases rapidly. Moreover, expected return on a fixed portfolio becomes indefinite (i.e., takes infinitely many values), and betas of all portfolios approach one. Unlike the Sharpe–Lintner CAPM, the market risk premium in the Black CAPM always has a positive minimum, while beta may have a negative minimum value, dependent on the underlying covariance matrix.