No tax on Roth IRA gains. Roth IRAs are contribution made after tax (if your income qualifies to participate). 401K and traditional IRAs are taxed upon withdrawal, unlike a Roth. Not sure about SEPs. It may be best to convert part of your IRA to a Roth IRA and pay taxes NOW. You're gonna have IRS adjustments, but if hope for or expect a major windfall, very much worth investigating. Plus, few limitations on withdrawals and on your Will (Inheritance/Beneficiaries). https://www.rothira.com/traditional-ira-vs-roth-ira UOIP, UOIP, UOIP, Scruffer :-)