Correct, Line 14 should show your total basis in your traditional IRA from all of your nondeductible contributions. It's possible that when you prepared your return in those years you didn't enter your basis so the form was prepared as if there were no prior nondeductible contributions.
If you didn't deduct your contribution made in 2019, you'll need to:
- file a Form 8606 to report your nondeductible contribution. Report your prior nondeductible contribution from 2018 on line 2 - this should be $3,600 from line 14 of the 2018 Form 8606. Line 14 of the 2019 Form 8606 should show a basis of $9,600.
- amend your 2020 Form 8606 to report the carryover basis from 2019.
- continue amending the Forms 8606 to report proper basis in your traditional IRA.
If your spouse didn't deduct the contribution made in 2019, they will need to:
- file a Form 8606 for 2019 to report their initial nondeductible contribution. Line 14 of the 2019 Form 8606 should show a basis of $6,000.
- amend their Form 8606 for 2020. Line 2 should be $6,000 which is carried over from the 2019 Form 8606. Line 14 will then increase to $12,000.
- continue amending the Forms 8606 to report the proper basis in your spouse's traditional IRA.
If the 2019 contribution was deducted, you will just need to amend your 2020 and subsequent forms and your spouse will need to amend their 2021 and subsequent forms to report the basis from prior years and correct the reported basis. You will need to convert your entire IRA balance to avoid the pro-rata rule. Otherwise, as long as there are nondeductible contributions in the account you will always have to include some of the conversion in income each year.
