As part of their fiduciary obligation financial institutions, buy-side firms need to demonstrate Best Execution for their clients. A key compliance role in meeting this obligation is to create an ongoing process to test for Best Execution by monitoring trade performance. There are many factors in measuring execution quality and some regional variations in regulatory requirements between the SEC, FCA, and ESMA. However, one near-universal aspect of Best Execution monitoring is systematic reporting and review of trading costs for “Outliers”. That is, orders with high costs outside the range of normal trading costs.