I want to do in-service roll-over from my "traditional after-tax 401k" employer savings plan to my "Roth IRA" (both accounts are administered by the same investment company). Would this be treated the same as a rollover from a traditional IRA to a Roth IRA (that is, that the amount of the rollover that would be tax-free would be based on the ratio of after-tax and pre-tax money in the 401k), or would it be tax-free (except for any earnings on after-tax contributions that haven't been taxed yet)? Thank you.

I want to do in-service roll-over from my "traditional after-tax 401k" employer savings plan to my "Roth IRA" (both accounts are administered by the same investment company). Would this be treated the same as a rollover from a traditional IRA to a Roth IRA (that is, that the amount of the rollover that would be tax-free would be based on the ratio of after-tax and pre-tax money in the 401k), ===========>>>>>>>>>> it depends. After-tax 401(k) is a type of deferred 401k subaccount typically used in strategies to rollover money to Roth IRAs far in excess of normal contribution limits; plenty of people do roll after-tax 401k funds directly to their Roth.when rolling a 401(k) with after-tax contributions to an IRA, the standard procedure used to be that the after-tax contributions would be paid to the employee while all the pretax moneys would go into an IRA. These days many want the after-tax contributions sent to a Roth IRA instead. Same process applies to after-tax 401k money that is rolled over to a Roth. Aslongas you rollover after-tax money directly to a Roth Ira, it seems your primary risk is that if the transaction is audited it may be considered to be a Roth conversion, and you would owe taxes on a pro-rata share of the amount rolled to the Roth. For example, if you had $10k of non-deductible contributions (after-tax) and $90k of deductible funds (before-tax) and you converted $10k to a Roth, 90% of the converted amount would be considered taxable income. So as you said if you had a lot of pre-tax money in your 401k, this could end up being a big tax bill.
Keep in mind that not all employer-sponsored plans allow for in-service withdrawals. Profit-sharing plans and 401(k)s may allow them, but money purchase pension and defined benefit plans do not.


or would it be tax-free (except for any earnings on after-tax contributions that haven't been taxed yet)?===============>>>>>>>>>>>>as mentioned above.