October 27, 2017 15:41 Updated Follow You can also make extra payments into your post-tax. This means your federal, state and Social Security taxes have already been withheld. Related articles How do I make voluntary post-tax contributions to my Annuity Savings Account? Am I allowed to make voluntary contributions to my PERF plan? Where do I find employer forms? Where can I find training resources for ERM? At what age should I retire?