Before revision:  We propose a class of informationally robust, dominant-strategy incentive compatible (DSIC) , and ex post individual rational (EPIR) mechanisms that are asymptotically ex ante budget balanced (AEABB) and asymptotically efficient (AE) as the population grows .
After revision:  We propose a class of informationally robust, dominant-strategy incentive compatible (DSIC) , and ex post individual rational (EPIR) mechanisms which we call the adjusted mean-thresholding (AMT) mechanisms. We show that when the cost of provision grows slower than the \sqrt{n asymptotically ex ante budget balanced (AEABB) and asymptotically efficient (AE) as the population grows .