Description: Regularization, by means of trading restrictions, is an effective way to obtain sparse replicating portfolios. By including only the most relevant replicating instruments, the resulting portfolio is more efficient computationally, easier to interpret, and better able to approximate the liability on an out-of-sample basis. The instruments selected depend largely on their respective trading costs. This paper evaluates a number of alternative methods for specifying trading costs. We find that trading costs based on simple statistics of the instrument and liability cash flows are an effective choice in practice. Presented at 2010 Enterprise Risk Management Symposium, Society of Actuaries, April 12-15, 2010.

Description: Since most cash flows being discounted in the value calculation are dependent on the forward rates, in the key-rate calculation forwards (not spots) should be shifted. I will show that if spots are shifted up/down, they would not necessarily result in forwards being up/down for all the years in the particular key rate, resulting in unexpected results. I will further show how metrics calculated by shifting forwards versus spots enhance the accuracy of the approximation of projected value in various rate environments.