The Iowa Electronic Markets are small, real-money financial markets designed to aggregate information about future events. The market microstructure of these markets is studied and a market making model is developed to provide liquidity for one set of securities offered by this exchange. A computer program was created to employ the market making model and profit from the market’s inefficiencies. Using invested capital, the system traded 34% of the total market volume and achieved a Sharpe ratio of 9.9. This paper reveals the details of how this algorithmic trader worked to show how it functioned and the value it added to the Iowa Electronic Markets.