Inherited Roth IRA taxable box checked on 1099

[Kimo4]

Mother passed away and I inherited her Roth IRA that she held for 19 years.

I cashed it out completely and the 1099-R I received said the entire amount is taxable but the box was also checked that the taxable amount is not determined.

I'm confused about the 5 year holding period.  Does it apply to me (less than a year) or to my Mom (19 years).

I thought it applied to my Mom which is why I cashed out and still figured I'd be tax free.

She made all contributions using post tax dollars so why do I have a 1099 that says the entire amount is taxable to me?  

I've tried inputting into one of the fields that the Roth IRA started in 2003 but the algorithm still wants to charge me full marginal tax rate.

Is there something I'm missing?  Another form to fill out?  

Can I claim the distribution but say none of it is taxable since the "taxable amount undetermined" box is checked and I know it's a long-held Roth IRA?

What would you do in my case?  The bank who generated the 1099 is very non responsive.  They require 3 business days to return any calls.  And that's just to return the call, not have an answer to your question.

[dmertz · Accepted solution]

The 5-year holding period began with your mother's first Roth IRA contribution.  Because that was well over 5 years ago, distributions paid to you as beneficiary are qualified distributions, free of any tax or penalty.