Retirement tax questions

2. In my case I never made any contributions either per-tax or after tax to the superannuation account ...  I wasn't really aware of it until I retired from the IBM US company.

 

Because IBM made contributions that were pre-tax (you did not pay tax on the contributions), my position is that the payout is 100% taxable in the US, unless there is a tax treaty that says different.   Someone else may know something different.