What is not a type of swap listed in financial literature?

The correct answer is based on the understanding of common swap types found in financial literature. In the context of swaps, a fixed-only swap does not represent an actual category of swap agreements. Rather, swaps typically involve exchanges between fixed and floating rates or different floating rates.

Callable swaps and putable swaps are specific types of interest rate swaps that include options allowing one party to terminate the swap early under certain conditions. Similarly, the zero-coupon-for-floating swap involves exchanging a zero-coupon bond for a floating rate obligation, which is a recognized structure in derivatives trading.

The term "fixed-only swap," however, does not align with standard nomenclature or recognized categories in the industry. Swaps inherently involve variations in interest payments that serve different hedging and investment strategies, including the interplay of fixed versus floating rates, making the notion of a fixed-only swap uncharacteristic of traditional swap structures.