APT is grounded in the principle of no-arbitrage, the idea that if two assets offer identical cash flows, they should be priced the same. Here's how it works:
Identify multiple macroeconomic or statistical risk factors that influence asset prices
Estimate each asset's sensitivity (beta) to these factors
Use the APT formula to determine expected return
If the actual price diverges from the expected return, arbitrage opportunities may arise until prices return to equilibrium
The model is flexible and allows investors to plug in factors relevant to their specific market or sector.
Arbitrage Pricing Theory Calculation Example
Suppose an asset is influenced by two key factors, interest rate movements and inflation.
Risk-free rate (Rf): 4%
Interest rate premium (F1): 2%, with a beta (β1) of 0.5
Inflation premium (F2): 1.5%, with a beta (β2) of 0.8
Using the formula:
Expected Return = 4% + (0.5 × 2%) + (0.8 × 1.5%)
= 4% + 1% + 1.2% = 6.2%
Thus, the expected return on this asset is 6.2%, which can be compared with the actual return to identify any price discrepancies.