Question: Does the increase in the investment limits for 401(k) plans apply to the Thrift Savings Plan, too?

Answer: Yes. The TSP for federal employees and military personnel operates under many of the same tax code provisions as 401(k)s, including what is called the “elective deferral limit.” That figure will rise to $18,500 in 2018 from $18,000. For those making both pretax and after-tax “Roth” investments, it applies to the combination.

That limit counts only personal investments and not agency contributions into the TSP accounts of employees under the Federal Employees Retirement System. They get an automatic employer contribution of 1 percent of salary, plus up to another 4 percent in matching contributions.

The TSP also mirrors general tax policy in allowing “catch-up contribution” investments by those who are age 50 or older in a year, if they reach the regular limit or are investing at a rate to hit it by the end of the year. That maximum will remain $6,000.

Regular investments continue year to year unless changed, so to take advantage of the higher limit you’ll have to make a new payroll withholding election in 2018. Catch-up contribution elections don’t continue; they must be made each year.