"...The Internal Revenue Service has increased the cap on annual individual contributions to employer-sponsored retirement savings plans, including the Thrift Savings Plan, to $18,000 for 2015.
The increase, which tracks changes in the cost-of-living index, is the first since 2013, when the cap rose to $17,500 from $17,000...
For military service members, the cap includes all traditional and Roth contributions from taxable basic pay, incentive pay, special pay and bonus pay, but does not apply to traditional contributions made from tax-exempt pay earned in a combat zone..."