This paper examines the ultimatum game preceded by a single player's investment
decision that is risky in that the business opportunity could fail to be discovered. The
experiment's results show that the functioning of social preference connecting the baseline
ultimatum game with the investment crucially depends on the model's specifications, such as
whether the proposer or the responder is the investor or the riskiness of the investment. The
noninvestor/proposer tends to act in consideration of the efficiency of the investment, but not its
riskiness. Such tendencies of the noninvestor's/proposer's social preferences are diametrically
opposite to that of the investor/proposer.