Arbitrage Pricing Theory

341 Words2 Pages
From Wikipedia: In finance, arbitrage pricing theory (APT) is a general theory of asset pricing that holds that the expected return of a financial asset can be modeled as a linear function of various macro-economic factors or theoretical market indices, where sensitivity to changes in each factor is represented by a factor-specific beta coefficient. The model-derived rate of return will then be used to price the asset correctly - the asset price should equal the expected end of period price discounted at the rate implied by the model. If the price diverges, arbitrage should bring it back into line. The theory was proposed by the economist Stephen Ross in 1976. Contents [hide] 1 The APT model 2 Arbitrage and the APT 2.1 Arbitrage in expectations 2.2 Arbitrage mechanics 3 Relationship with the capital asset pricing model (CAPM) 4 Using the APT 4.1 Identifying the factors 4.2 APT and asset management 5 See also 6 References 7 External links [edit]The APT model Risky asset returns are said to follow a factor structure if they can be expressed as: where is a constant for asset is a systematic factor is the sensitivity of the th asset to factor , also called factor loading, and is the risky asset's idiosyncratic random shock with mean zero. Idiosyncratic shocks are assumed to be uncorrelated across assets and uncorrelated with the factors. The APT states that if asset returns follow a factor structure then the following relation exists between expected returns and the factor sensitivities: where is the risk premium of the factor, is the risk-free rate, That is, the expected return of an asset j is a linear function of the assets sensitivities to the n factors. Note that there are some assumptions and requirements that have to be fulfilled for the latter to be correct: There must be perfect competition in the market, and the

More about Arbitrage Pricing Theory

Open Document