This paper examines the optimal auction design problem with one regular buyer and one speculator, when inter-buyer resale can not be prohibited.  The resale is a stochastic ultimatum
bargaining game. In the optimal mechanism, the winner in the initial market, if any, is always the speculator and the seller reveals no information to the resale market. In general, this optimal mechanism generates weakly less revenue than in the case resale is not permitted. However, the revenue is the same when the winner has all the bargaining power in the resale market. {When the loser has all the bargaining power in the resale market, an efficient outcome is optimal.} The chance of resale makes the seller sometimes hold back the object, which is never optimal in our model if the seller can prohibit resale.