Further One-Factor Term-Structure Models

The academic literature and market participants have proposed a large number of alternatives to the Vasicek term-structure model and models, such as the Hull-White model, that are based on it. Like those they seek to replace, each of the alternatives has advantages and disadvant es. 

The main advantage of Vasicek-type models is their analytic tracta-bility. Their main weakness is that they permit negative interest rates. Negative interest rates are not impossible in the actual market a bond 

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