  In the private values single object auction model, we construct a
satisfactory mechanism - a symmetric, dominant strategy incentive compatible,
and budget-balanced mechanism. Our mechanism allocates the object to the
highest valued agent with more than 99% probability provided there are at least
14 agents. It is also ex-post individually rational. We show that our mechanism
is optimal in a restricted class of satisfactory ranking mechanisms. Since
achieving efficiency through a dominant strategy incentive compatible and
budget-balanced mechanism is impossible in this model, our results illustrate
the limits of this impossibility.
