We solve the problem of optimal securitization for an issuer facing heterogeneous investors with arbitrary time and risk preferences. We show that the optimal securitization is characterized by multiple nonlinear tranches, and each investor gets a portfolio of these tranches. In particular, when...

We study optimal securitization of defaultable assets in a continuous time setting. A financial intermediary can create a portfolio of defaultable assets and then sell it to outside investors. The default risk of the assets in the portfolio is determined by the unobservable costly effort exerted...