I opened a TD bank checking account as a foreign tourist in 2013. I had filled the w8-ben form. Recently, I received a letter from the bank asking me to update my occupation because they didn't have in on file. Now they have sent me another letter asking for proof of foreign citizenship to avoid U.S withholding tax. They have also enclosed a W8-ben form.
I have spent less than 15 days in the USA last year and I receive no USA income. What exactly us the purpose of a W8-ben for a checking account? Under what circumstances can the bank withhold taxes? I receive no interest from the account.