Is it permissible to open an investment account in a usurious bank (such as Banque Saudi Fransi) for online trading of local shares, without having any other current dealings with the bank?

If it is necessary to deposit money into an account, then it is not permissible to open it due to the assistance it provides to the bank in usury. However, if it is not necessary, and an Islamic bank is available, then it is not permissible to open an account in a usurious bank. Otherwise, it is permissible, provided that the stock trading is conducted according to Sharia regulations.