The Thrift Savings Plan (TSP) is a defined contribution retirement savings and investment plan that offers Federal employees the same type of savings and tax benefits that many private corporations offer their employees under 401(k) plans. By participating in the TSP, Federal employees and uniformed service members can save part of their income for retirement, receive matching agency contributions, and reduce their current taxes., My Account. TSP Account Number. User ID. Forgot your account number or user ID? My Account, Plan Participation, Investment Funds, Planning and Tools, Life Events and , The Thrift Savings Plan (TSP) is a defined contribution retirement savings and investment plan that offers Federal employees the same type of savings and tax benefits that many private corporations offer their employees under 401(k) plans..