Roth401K的亮點

• Roth降低retirement AGI。AGI defines other tax and other costs (Medicare premium...)
• Roth 401K，如果公司offer，好於Roth IRA：higter contribution amount, no income limitation 
• Roth 401K actually can contribute more more than regular 401K. (Same amount valued more on retirement withdrawal time).同樣放滿，Roth其實是多放了tax那部分。
• Uitill 2025,the marginal tax rate is historically low. If can stay within same tax bucket, could consider converting IRA to Roth IRA.
• Rollover to Roth IRA tax free. (10 reasons to buy Roth before tax deadline https://www.forbes.com/sites/financialfinesse/2020/07/13/why-you-might-want-to-contribute-to-a-roth-ira-by-july-15th/#405b8bc75611 )
• All Roths: after 5 years, withdrawn original investment amount penalty free.
• Roth IRA only: No RMDs after age 72.

退休以後還要注意每年的MAGI。如果高了，許多tax credits 不適用於高AGI。Medicare premium 會隨著AGI的升高而增加。

PS

form 8606 backdoor Roth 算法：rollover $2，after tax contribution $2， (Assuming no gains)

• convert to Roth $2: $1 towards income base, $1 免稅，$1 after tax base carry over, IRA = $2, Roth IRA = $2 
• convert to Roth $4: $2 towards income base, $2 免稅，$0 after tax base carry over, IRA = $0, Roth IRA = $4