The Thrift Savings Plan (TSP) is a retirement savings and investment plan. It is an essential part of FERS and a great supplement to CSRS. Changes in your contributions are made in myPay. Changes to your allocations are made through TSP Account Access or by calling the ThriftLine (1-877-968-3778). Additional Information Plan Participation Investment Funds Planning & Tools Life Events Support Forms and Publications Informational Videos How TSP Fits In FERS Program Overview How TSP is Portable Please note that only videos identified as “USOPM” are authorized by OPM and the TSP.