The PBGCbacks up thepension plansof private corporations.Corporations pay intothe PBGC fund.If the company's pension plan goes belly up then the PBGC picks up the tab. One of the first and largest pension plans to goinsufficientwas the railroad retirement fund in about 1973.
Currently,the PBGC has a funny balance on the books.Taxpayers are going to have to pick up much of the tab asmore companies and pension plans go insolvent. The PBGC lost 3 billion dollars when the stock market tanked.
Note the failures just this year.
http://www.pbgc.gov/