Multiple Roth IRAs

[ljt96]

I opened my first Roth circa 1999 and still have it (although it's been with a few different brokers). I opened another, new Roth IRA when I started taking Roth Conversions in 2019.  I am over 59 1/2.  Because my withdrawal should come with a distribution code "T" I don't expect to have to enter my prior year contributions, but if I did my understanding is that the Roths are considered in aggregate so even if the broker who holds my Roth with conversions only, I would be entering the contributions from the other older Roth.

If that is true, then would that also apply if I took distributions from the Roth with conversions before they had aged five years that the IRS would still count whatever cost basis is left in my contribution Roth against those conversions first ? 

[Opus 17]

I don't actually know whether contributions, conversions and earning are considered per account or in aggregate, but if you are over age 59-1/2, and because your first Roth account was opened more than 5 years ago, it doesn't matter.  All your withdrawals are tax-free.  Specifically,

1. Withdrawal of contributions is always tax-free
2. Withdrawals of conversions is free from regular income tax, but may be subject to a 10% penalty if you are under age 59-1/2
3. Withdrawal of earnings is subject to income tax if the account is less than 5 years old or you are under age 59-1/2, and a 10% penalty if you are under age 59-1/2.

[dmertz]

All of your Roth IRAs are qualified because you are over age 59½ and it has been more than 5 years since the beginning of the year for which you first made a Roth IRA contribution.  Because your Roth IRAs are qualified, any distribution that you take from any of your Roth IRAs is free of any tax.

As you said, your Roth IRAs are treated in aggregate as if all of the funds were in a single Roth IRA.  Technically, your contribution basis still comes out first no matter which Roth IRA the distribution comes from, but that is pretty much irrelevant since your Roth IRAs are qualified.  You basis in Roth IRA contributions and conversions belongs to you, not to any particular one of your Roth IRAs.