Both assume unlimited borrowing and lending at the risk free rate.
ICAPM becomes Extended CAPM when international capital markets are integrated and Purchasing Power Parity holds.
ICAPM can be used to value any security in the world if all national markets are integrated.
ICAPM indicates that if global markets are integrated and efficient, then the optimal portfolio is global market index hedged based on the investor's currency exposures to the foreign assets in the index.
Investor time horizon influences application of ICAPM.
