[Excerpt] The Pension Benefit Guaranty Corporation (PBGC) was established by the Employee Retirement Income Security Act of 1974 (ERISA) to ensure that participants in defined benefit pension plans receive their pensions if their plans terminate without sufficient assets to pay promised benefits. PBGC administers separate insurance programs to protect participants in single-employer and multiemployer plans. PBGC has published the Pension Insurance Data Book annually since 1996 to present detailed statistics on PBGC program operations and benefit protections. This edition of the Pension Insurance Data Book contains two short articles. The first article is an update of PBGC’s December 2005 study on frozen plans. The second is an update of a 1999 PBGC study on the effects of PBGC’s benefit limitation provisions on the benefits of participants in the plans PBGC trustees. PBGC made no changes in the accompanying data tables other than updating the data included. The Data Book is available on PBGC’s Web site at www.pbgc.gov/publications/databook.