Large Companies borrow money from the public sometimes. In exchange for this money, they give the lenders a certificate showing the details of how much they owe, when they will pay it back, and the interest they will pay for it. That certificate is called a Commercial Paper (CP), and it can be traded by the lender to another party in an organised financial market structure. The interest doesn’t change over time, so it is said to be fixed and like treasury bills, it is also paid upfront at the beginning of the agreement. This is why commercial papers are referred to as Discounted instruments.