President Bush has proposed adding optional personal accounts as one of the central elements of a major Social Security reform. proposal. Although many details remain to be worked out, the proposal would allow individuals who choose to do so to divert part of the money they currently pay in Social Security taxes into individual investment accounts. Individuals would have a choice of fund managers, and the return that they earn from those accounts would then partially determine the Social Security benefit they receive when they retire. Individual accounts pose a number of important and complex design and implementation issues, including how to lower the cost of administering accounts so that they do not erode the value of pensions that individuals receive when they retire, how many and what kinds of fund choices should be offered, and how to engage workers in choosing funds. In the late 1990s, Sweden added a mandatory individual accounts tier to its public pension system. This p01icy brief examines the Swedish experience and lessons it suggests for the United States about the design and implementation challenges of individual accounts. Sweden has one of the oldest and most comprehensive public pension systems in the world. But by the 1980s, several problems with the system were becoming evident, including current funding deficits and a very large projected funding shortfall as Sweden's population, which is among the oldest in the world, continued to age. Between 1991 and 1998, Sweden adopted a new pension system built on three fundamental elements. A new 'income pension' is intended to tie pension benefits more closely to contributions made over the entire course of an individual' s working life, while lowering the overall cost of the system it is financed entirely by a 16 percent payroll tax. A 'guarantee pension' provides minimum income support for workers with low lifetime earnings. It is financed entirely by general government revenues and is income-tested against other public pension income. The third element is a 'premium pension' financed by a 2.5 percent payroll tax. These funds are placed in an individual investment account. Individuals have a wide variety of fund choices. To lower administrative costs and the administrative burden on employers, collection of premium pension contributions and fund choices are centrally administered by a new government agency, the Premium Pension Authority. Deposits into pension funds are made only once a year, after complete wage records for a calendar year are available from the state tax authorities. Employees choose up to five funds from a list of funds approved by the PPA. Swedes can change their fund allocations as often as they want without charge, but the system is not designed to facilitate 'day trading'—switching funds often takes several days. The new pension system's planners recognized that many workers might not make an active pension fund choice. They created a Seventh Swedish National Pension Fund to offer a default fund, called the Premium Savings Fund, for those who do not choose a fund or simply prefer to have the government invest for them. What can you learn about Bush's proposal of adding optional personal accounts?