We're happy to share our fourth progress report summarizing our work during the second half-year of 2021. As explained in the strategy section, we primarily focused on building research software tools in collaboration with other AI governance researchers such as Associate Professor Robert Trager and Shahar Avin while also revising and substantially extending our technical report about our evaluation of the Windfall Clause policy. The progress report elaborates on these accomplishments and the roadblocks we encountered and mentions any updates regarding our team members and future goals since our previous progress report.