There's a 44 day hold on funds deposited by ACH. Within that period you can transfer the funds back to the originating bank but not to others. Don't know if that's relevant in your case. Generally the funds available for withdrawal is equal to your "Current Available Funds" in the account window. This is actually one of the rare instances where IB support can be useful, as they can see what holds your account might have. Just open a chat in the background and go about your day until someone connects.