Outside of the US Federal Government, it is not possible to search for bank accounts with just a social security number. The IRS receives information from bank accounts held by US citizens, which are linked to them using social security numbers. Participating banks across the world are required to collect this information from US citizens and to submit the information to the IRS. As social security numbers – and bank account numbers – are generally considered sensitive information, an individual is unlikely to be able to access this information through normal channels. There may be legal challenges that can be made to compel an individual bank to check, but there is no blanket way to check all banks.