The investment seeks to track the investment results of an index composed of mid-capitalization U.S. equities while applying screens for company involvement in controversies and controversial business activities. The fund seeks to track the investment results of the S&P MidCap 400 Sustainability Screened Index, which measures the performance of the mid-capitalization sector of the U.S. equity market while excluding companies involved in controversial business activities and controversies, as determined by S&P Dow Jones Indices LLC. BFA uses a representative sampling indexing strategy to manage the fund. It is non-diversified.