In order to update the list of ticker symbols in Excel you must manually export them from Thinkorswim. Therefore Thinkorswim is not able to push a new list of ticker symbols into Excel. Add specified text to the beginning / end of all cells with VBA If you want to add specified text in each cells of a selection directly, the following VBA Macro will ease your work.
Kutools for Excel: with more than 300 handy Excel add-ins, free to try with no limitation in full future 30 days.