Page "Put–call parity" Paragraph 5

Let the price of S be S ( t ) at time t. Now assemble a portfolio by buying a call option C and selling a put option P of the same maturity T and strike K. The payoff for this portfolio is S ( T )-K. Now assemble a second portfolio by buying one share and borrowing K bonds.

Note the payoff of the latter portfolio is also S ( T )-K at time T, since our share bought for S ( t ) will be worth S ( T ) and the borrowed bonds will be worth K.