On Thursday, President Joseph Biden proposed new federal rules that would require companies with more than 100 workers to either mandate COVID-19 vaccinations or require that those who aren’t inoculated be tested weekly.

Given the fact that almost all of the Am Law 200, as well as many midsize firms outside of the group, are in this size range, the proposed rule would have wide-ranging effects for law firms. And it raises some questions about implementation and costs.