US based.
I just learned about something called "back door Roth IRA". It is a process that allows one to contribute non-deductible (after tax) funds to an IRA account and then do a Roth conversion into a Roth IRA account. This way, you are taxed on your income that you contribute to the account, but all your future earnings stay tax and penalty free forever.
I am confused by this so much! Why in the world would anyone put their after tax investments into a regular taxable brokerage account instead of doing a backdoor Roth conversion? There is no difference in immediate taxes -- you are still paying your current year marginal tax rate on your income before contributing to the account. I guess it makes a difference for people who have no ordinary taxable income (people living off of their investment income that has a lower capital gains tax rate). But for anyone who works a normal job or is self-employed and pays regular income tax, there is no difference.
There is no limit on how much you can invest. There are no income limits. You already paid income tax on the money you are contributing, so there is no additional taxable event. All your capital gains and dividends, etc. are completely tax free, which simplifies your tax accounting. You can withdraw original contributions any time tax free and penalty free. As long as you satisfy the 5 year rule, you can withdraw your earnings tax and penalty free once you are 59 1/2 years old. I guess this could be viewed as a limitation, but I think most people would not be affected by this because they are still working at that age.
You can make an argument that this is not available to everyone because many people already have pre-tax funds sitting in a traditional or rollover IRA account, so the Roth conversion will be taxed on the blend of your pre-tax and post-tax money. However, there is an easy way around it for many people with regular jobs -- just do a reverse rollover from all your post-tax IRA accounts to your employer 401k plan, assuming they support incoming rollovers from IRAs. Then, once you have zero pre-tax funds remaining in your IRA accounts, you can do the Roth conversion on just your nondeductible contributions.
Can anyone please confirm my understanding of this approach and try to poke holes in it? Thanks!