Replicating portfolio
From ACT Wiki
A risk neutral method of valuing options and other financial instruments.
For example a replicating portfolio for an option consists of a combination of the underlying asset and a theoretical risk-free borrowing or deposit, that produces the same payoffs at maturity as the option being valued.
Applying no-arbitrage assumptions, the value of the replicating portfolio at Time 0 is therefore equal to the theoretical value of the option at Time 0.