This paper studies equilibria of second price auctions when values and participation
costs are both privation information and are drawn from general distribution functions. We
consider the existence and uniqueness of equilibrium. It is shown that there always exists an
equilibrium for this general economy, and further there exists a unique symmetric equilibrium
when all bidders are ex ante homogenous. Moreover, we identify a sufficient condition under
which we have a unique equilibrium in a heterogenous economy with two bidders. Our
general framework covers many relevant models in the literature as special cases