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13
votes
2answers
571 views
Why isn't the Nelson-Siegel model arbitrage-free?
Assume $X_t$ is a multivariate Ornstein-Uhlenbeck process, i.e.
$$dX_t=\sigma dB_t-AX_tdt$$
and the spot interest rate evolves by the following equation:
$$r_t=a+b\cdot X_t.$$
After solving for $X_t$ ...
4
votes
1answer
155 views
How to scale option pricing components in regard to time
I am looking at closed-form options approximations, in particular the Bjerksund-Stensland model.
I have run into a very basic question. How should I scale the input variables in regard to time? My ...
