Most Recent Assignment Execution Date (ANRE_EXE_DT)
When a patent changes hands an assignment may be recorded at the USPTO. Because patents are often assigned many times over their lives, it is useful to be able to query the most recent assignment date. Use the ANRE_EXE_DT field code to query patents by their most recent assignment execution date.
As with other date fields you can use it with a date range or a single date.