I agree, CUSIP is also a problem for the privateer (meaning all data needs to be free to use). While I have found a way to find a mapping online, I have no idea

I agree, CUSIP is also a problem for the privateer (meaning all data needs to be free to use). While I have found a way to find a mapping online, I have no idea of the accuracy and have to trust that the unaware provider QA's the data.