ON A 1099R OFFICE OF PERSONNEL MANAGEMENT; WHEN BOX 2A IS UNKNOWN AM I TAXED ON THE AMOUNT IN BOX 1

[Luckeynay]

AM I TAXED ON THE ENTIRE AMOUNT IN BOX 1.  THIS IS MY XHUSBANDS RETIREMENT

[NCperson]

@Luckeynayyes, unless there is something in Box 9b

[dmertz]

You would need to determine the amount of after-tax contributions made to the plan and, if so, use the Simplified Method to calculate the taxable amount; TurboTax has the ability to do the Simplified-Method calculation based on your input.  Otherwise, the entire amount is taxable.  If you use the Simplified Method, the IRS will like ask for documentation supporting your claim of the amount of after-tax contributions to the plan.

[NCperson]

@Luckeynay the "simplified method" is part of Turbo Tax.  as you asnwer the questions about the 1099-R, once TT realizes there is nothing in box 2a, it will ask you to complete a series of questions so it can complete the Simplified Method. 

Again, if Box 9b is zero, it's all taxable.  

[dmertz]

Box 9b is informational only and is optional for the plan to provide whether it knows the amount of employee contributions or not, so lack of an entry in box 9b does not necessarily mean that there were no after-tax contributions.  If the plan doesn't know enough to determine the taxable amount of a distribution, there's a good chance that the plan also does  not have the information needed to populate box 9b.

[NCperson]

@dmertz in my experience - and it makes no sense, OPM (federal Office of Personnel Management), frequently leaves Box 2a blank but populates Box 9b.  Why they don't calculate Box 2a,given they know Box 9b is a mystery.

[dmertz]

Still, in general, a blank box 9b cannot unambiguously be interpreted as meaning that there were no employee contributions.  Absence of evidence is not evidence of absence.  However, if box 9b is blank and one cannot substantiate via some other means that there were employee contributions, one would have to operate as if there were none and treat the entire distribution as taxable.

[dmertz]

OPM provides some explanation here:

https://www.opm.gov/faq/retire/1099r-taxable-amount-is-listed-as-unknown-what-does.ashx

[NCperson]

@dmertz I was focused on where box 9b was populated,..... those are the ones where I see box 2a being blank.... but your link explains it: when there are voluntary contributions, they don't populate Box 2a, which is crazy! they should have all the information required to populate it.  

in y expereince, 9 times out of 10, use of the Simplified Method is driven by OPM retirees 1099-Rs.