Simudyne provides funds with an artificial market for the testing of execution strategies. The market is filled with a population of highly realistic virtual trading agents. Because the virtual traders attend to market conditions and current price as part of their buying and selling, the overall artificial market is responsive, dynamic and adaptive — just like a real market. By understanding how to adjust individual trade size, timing and execution, fund managers can accelerate the reduction of these implicit equity execution costs. By accurately forecasting transaction costs, they capture the value that they are leaving on the table. Furthermore, they can run an order of magnitude more counterfactual scenarios to discover the parameters which provide the best outcome. This generates savings and preserves alpha.