A swap transaction is basically a barter transaction. I give you a cow, and you give me 10 chickens. What value did I receive for my cow? I received the value of 10 chickens. What value did you receive for your chickens? I paid you the value of one cow. Both of us thought that what we received—in my case, chickens—was worth an amount equal to or greater than what we gave up, in my case, a cow.