Criteria for initiation of highly active antiretroviral treatments (HAART) in HIV-infected patients remain a matter of debate world-wide because short-term benefits have to be balanced with costs of these therapies, and restrictions placed on future treatment options if resistant viral strains...

We consider a firm that must undergo a costly and time-consuming regulatory process before making an irreversible, lagged investment whose value varies randomly. We analyze two cases: regulatory approval is valid forever or it expires after some time. We apply our model to Hydro Québec's...