To be clear, it's a misnomer to call any particular traditional IRA account a nondeductible IRA (even though Form 8606 is titled "Nondeductible IRAs"). What you have are nondeductible traditional IRA contributions." Basis in nondeductible traditional IRA contributions do not reside in any particular one of your traditional IRAs (unless you have only one) but apply to your traditional IRAs in aggregate. Multiple traditional IRAs of a particular participant are treated as a single IRA for the purpose of determining the taxable amount of a distribution (other than an HFD or QCD) from any one of the participant's IRAs. In this case, though, the fact that you have only one traditional IRA account means that the basis can only be associated with that one traditional IRA.
