Yes, I’m looking at you Schwab. BrokerageStatementMMDDYYACCT.pdf is not a sane filename.

for name in $(find . -name 'Brokerage*pdf' ); do new=$(echo $name |  sed  -re 's/BrokerageStatement([0-9][0-9])([0-9][0-9])([0-9][0-9]).*.pdf/Schwab-20\3-\1-\2.pdf/') ; mv $name $new ; done

Not the cleanest sed and shell, but you know, it works.

American dates and brokerages