My aunt died in 2018. SSA sent her a check in 2019 to fix an underpayment error. 1099 for 2019 was recd under her SSN, not her EIN. How do I handle this?

All income your aunt would have received had death not occurred, that wasn't properly includible on the final return, discussed earlier, is treated as “income in respect of a decedent”. 

Refer to IRS Publication 559 at this link for instructions on how to report this income.  These instructions include this:

 

Income in respect of a decedent must be included in the income of one of the following.

• The decedent's estate, if the estate receives it.
• The beneficiary, if the right to income is passed directly to the beneficiary and the beneficiary receives it.
• Any person to whom the estate properly distributes the right to receive it.

 

You may also be interested in this IRS website for filing a decedent tax return.

David, thanks for the reply.    A  few follow-up questions:   The check was deposited in the estate bank account and then distributed to me (I am the sole heir and Personal Rep for the estate).     If I opt to exclude this from the Estate 1041 and report it directly on my personal 1040, on what line would I record this income?   And since the 1099 was under my deceased aunt's SSN, how would the IRS know that this income has been properly reported on my return?  There doesn't seem to be an IRS audit trail here...just trying to avoid an audit trigger.  

As I read Publication 559, the estate must include the income on the Form 1041 if the estate receives it.