General Proof of Modigliani-Miller Propositions I and II using Parameter- Preference Theory
The following proof of Modigliani and Miller's (MM) [2] famous propositions concerning the valuation of the firm and the cost of capital does not require the usual risk-class or arbitrage assumptions; the proof depends only on the Fundamental Theorem of Parameter-preference, which states that the riskpremium for security A is a linear combination of its comoments with the market index, .