Active employees who are age 50 or above, or will be before the end of the year, and who wish to make “catch-up” contributions to the TSP will have to file a form TSP-1-C this year to make those contributions. Unlike regular TSP investing, catch-up contribution elections do not carry over from one year to another. The maximum allowable catch-up contribution is $5,000 this year, the same as last year. Catch-ups are allowed once an individual has hit the annual dollar TSP limit ($15,500 this year) or is on an investing pace to do so by the end of the year.