I have just changed jobs and was wondering should I keep my 401 (k) account separate from last job and new job? Or convert it to IRA?


You really have five options with an old 401K or 403B and need to choose from them based on your situation.

1) Do Nothing

If your old 401K was particularly low expense, or if there were some unique investment options such as the TIAA-CREF Real Estate Fund, a nice stable value fund, or the TSP G Fund, or if you new 401K has lousy options or high expenses, then just leave the money in your old 401K.  Usually there’s no problem with that as long as there’s more than a couple of thousand dollars in the account, but check your 401K Plan Document to be sure.  This is what I did when I left the military since the TSP not only has rock-bottom expenses, but also the very unique G Fund.

2) Roll It Over To A Traditional IRA

This can be a great option if you’re not interested in a Backdoor Roth IRA.  Most docs either ARE or SHOULD BE interested, so this probably isn’t that good of an option for a high earner.  The benefits of a traditional IRA over a 401K can include lower expenses and more investment options.  Downsides include loss of the Backdoor Roth IRA option and in some states, less asset protection than a 401K.  But if it’s a large 401K balance, your old 401K had lousy investments or high expenses AND your new 401K has lousy investments or high expenses, then this might be your best option.

Keep in mind that rules get a little more complicated if any of your 401K is a Roth subaccount.  When rolling it over to an IRA tax-deferred money goes into a traditional IRA and tax-free money goes into a Roth IRA.  I have read but have been unable to confirm in an IRS document that EARNINGS on tax-free money go into the traditional IRA unless the account has been open for at least 5 years.  Keep in mind that if you’re near retirement age, the rollover resets the 5 year period before you can take Roth distributions, so you might not want to do that.
3) Convert it all to a Roth

Sometimes its just easier to bite the bullet and pay the taxes.  This is a good option if both 401Ks suck, if the balance isn’t that big and you have money elsewhere to use for the taxes due, and you DO care about backdoor Roth IRAs.  Or perhaps you just want more Roth space for some other reason.

4) Roll it all over to the new 401K.

If you want to have the Backdoor Roth IRA option, and your new 401K is clearly better than the old one,  or if you highly value simplification of your finances, then the easiest thing to do is often to just roll the old 401K into the new one.  Keep in mind with a Roth 401K that this resets the “5 year period” to the establishment of the new Roth 401K, so be careful if doing this just before retirement.  If you have an even older 401K that you kept in the past because it was good (like my old TSP account) you could also roll it into there if the plan allows it.

5) Cash It Out

You can always take the money out, pay the taxes and penalties due, and spend it on a boat.  I told you there were 5 options, not 5 good options.  If you have a tiny balance in the 401K, this is sometimes the easiest thing to do.  I suppose if you’re over 59 1/2 and beginning to spend 401K money (perhaps only working part-time and relying on retirement money for part of your income), you might as well start 401K withdrawals now.