Background:
I am retired and younger than 59.5. I am converting up to the NIIT threshold ($250k) this year. I need to make sure I have enough taxes paid during the year through withholding or make estimated tax payments. I do not want to do estimated tax payments. They are due quarterly, and it involves learning how to pay taxes to the federal government and Colorado. Withholdings are so much easier and robust. You can do all your withholdings anytime throughout the year.
What I did:
I did a direct partial rollover from my 401k at Fidelity to my IRA at Fidelity. That is not a taxable event.
I then did a Roth conversion of the amount I rolled over from my 401k. That is a taxable event. I could either have taxes withheld at time of conversion or make an estimated tax payment. I don't want to make estimated tax payments, so I had taxes withheld. If I left it at that, I would have a 10% penalty and not all the money would find its way to the Roth. I don't want the 10% penalty, and I want all the money to find its way to the Roth. That is why I did a 60-day rollover. It gets all the money to the Roth, which I want, and it prevents the 10% penalty.
Summary:
$100k partial direct rollover from 401k to rollover IRA
Convert $100k in IRA to Roth and have $12k withheld for federal taxes and $8k for Colorado taxes
$20k 60-day rollover from my Fidelity CMA to my Roth
$100k from 401k is now in my Roth
$20k is gone from my taxable CMA account for taxes
Taxes paid by withholding