A risk measure for options which is computed by relating an option’s theta to its gamma:

Gamma rent = decay/gamma

This second-order greek , which is also known as alpha, expresses the quality of gamma in terms of the time decay (rent). Therefore, it indicates the quality of the earnings from gamma for one dollar invested in options for one day. A high gamma rent implies that the premium receiver does not receive sufficient earnings for the costs of the decay. A low gamma rent reflects the fact that the option trader is getting more for less (more gamma and less theta). Typically, generating higher gamma rents (for sellers) and lower gamma rents (for buyers) can be achieved by buying options for low premiums and selling options for high premiums.