High Quality Content by WIKIPEDIA articles! Social insurance is any government-sponsored program with the following four characteristics: the benefits, eligibility requirements and other aspects of the program are defined by statute; explicit provision is made to account for the income and expenses (often through a trust fund); it is funded by taxes or premiums paid by (or on behalf of) participants (although additional sources of funding may be provided as well); and the program serves a defined population, and participation is either compulsory or the program is heavily enough subsidized that most eligible individuals choose to participate.