May 15 - July 31.
Participants can choose to invest in any combination of the three funds.
This means the contributions made to TSP come out of the participant's pay before taxes and the earnings are not taxed until the money is received. Other benefits of the TSP program include a choice of investment options, interfund transfers, loans from the employee's own contributions and earnings, in-service withdrawals and portable benefits if the individual leaves federal service. Employees covered by the Federal Employees Retirement System can contribute up to 10 percent of their basic pay each pay period and the government will provide matching funds up to 4 percent. In addition, the government will contribute an automatic 1 percent of an individual's basic pay to their account each pay period whether they contribute or not. This brings the maximum government contribution to 5 percent.