We received a letter from the IRS stating that I had a substantial tax understatement penalty on our 2018 taxes in the amount of $1,714. 1040, Line 10, 11, and 13?

[stephensteiner]

Changes to our 2018 tax return
Income and deductions
Retirement income taxable
     Shown on Return $0
     As corrected by IRS $37980
      Difference  $37980
 Interest
      Shown on Return $0
     As corrected by IRS $101
      Difference $101
Retirement income gross
Shown on Return $0
     As corrected by IRS  $597
      Difference  $597

[Bsch4477]

If you did not have retirement and interest income tell that to the IRS. 

[Anonymous]

somehow the IRS has 1099's with either your spouse's or your SSN on them.  are you sure that one of you didn't forget about the income they received. By the way with the IRS saying you had about $39,000 more income than reported you would have to owe a lot more in taxes for there to be a substantial; underpayment penalty. 

i suggest you use

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