Abstract Consider a seller who can make an observable but non-contractible investment to improve an intermediate good that is specialized to a particular buyerʼs needs. The buyer then makes a take-it-or-leave-it offer to the seller. The seller has private information about the fraction of the ex post surplus that he can realize on his own. Compared to a situation with complete information, additional investment incentives are generated by the sellerʼs desire to pretend a strong outside option. On the other hand, ex post efficiency is not attained since asymmetric information at the bargaining stage sometimes leads to inefficient separations.