Employee contribution limit of $17.5k/yr for under 50 in 2013; $23k/yr for age 50 or above; limits are a total of pre-tax Traditional 401(k) and Roth 401(k) contributions. Total employee (including after-tax Traditional 401(k)) and employer combined contributions must be lesser of 100% of employee's salary or $51k ($56.5k for age 50 or above). There is no income cap for this investment class.
Source:
http://en.wikipedia.org/wiki/Comparison_of_401(k)_and_IRA_accounts
Another Explanation:
http://www.bogleheads.org/wiki/After-tax_401%28k%29
Know I know what you are thinking. "Why on earth would you want to get taxed twice?!" Well... as I understand it, TSP happens to allow for in-service distributions/rollovers" after a certain vesting period. I could, in theory, roll over that $33,500 into my Roth IRA, bypassing the $5,500 annual limit (Because it would be a rollover). Yes, the $33,500 would be after-tax dollars, however, I would be able to contribute them to a Roth IRA instead of a brokerage account.
Any thoughts? I guess my question is whether or not TSP enables these extra contributions.
EDIT: Fixed URL