I made a non-deductible contribution to a traditional IRA in 2018; that contribution was 100% of the balance in that IRA. Early in 2019 I converted that to a ROTH IRA, expecting that I would pay no tax as it was 100% of the value of the Traditional IRA (and no real change in value from the initial contribution). However, later in 2019 I rolled-over my 401k from a previous employer into a traditional IRA. Is the basis for the conversion earlier in 2019 what it would be at the time I did the conversion (effectively 100%), or is it the percentage of total Traditional IRA balances at the end of 2019 given the larger balance that exists because of the 401k rollover? Thanks.
