Which retirement savings account withdrawal is not subject to a 10% penalty before the age of 59½?

The withdrawal of basis from a Roth IRA is not subject to a 10% penalty before the age of 59½ because contributions to a Roth IRA are made with after-tax dollars. This means that you can withdraw your original contributions (or basis) at any time tax-free and penalty-free. The IRS rules allow for this flexibility since the contributions are made with money that has already been taxed.

In contrast, withdrawing earnings from either a Roth IRA or a traditional IRA typically incurs penalties if taken before reaching the age of 59½, unless certain exceptions apply. Traditional IRA withdrawals generally face taxes and penalties for early withdrawals, as those contributions were made pre-tax. Thus, understanding the distinction between contributions and earnings in retirement accounts is crucial for effective retirement planning and tax management.