In response to a congressional request, GAO assessed issues relating to the portability and preservation of private pension benefits, specifically: (1) whether job mobility adversely affected retirement income; (2) what kinds of portability and preservation arrangements existed and the extent to which they were used; and (3) the problems and tradeoffs involved in implementing proposals to enhance portability or preservation of pension benefits. GAO found that: (1) for workers with defined benefit plans, changing jobs would usually result in lower retirement incomes, since benefits and tenure usually do not transfer to another plan and plans base benefits on workers' earnings at the time they leave the plan, rather than their earnings at retirement; (2) workers who participate in a series of defined plans should not lose their retirement income if they keep their benefits in their previous plans, transfer them to subsequent plans, or convert them into individual retirement accounts (IRA); (3) pension preservation is a concern, since many workers spend, rather than reinvest, their cashed-out pension benefits; (4) some multi-employer plans and single-employer plans with reciprocity agreements allow plan portability, but cover less than 20 percent of the private-sector plan participants; (5) IRA are available as a pension preservation mechanism to all workers; (6) only 6 percent of all pension plans accept assets transferred from other plans; and (7) proposals to enhance portability and preservation would give workers better retirement benefits, but would increase employer costs and cause tax revenue losses.