A final plan is expected to be unveiled in late February. President Bush has not made a final decision on the plan's details.

The official, who spoke on condition of anonymity, said the size of the private accounts could be similar to a proposal by Sen. Lindsey Graham, R-S.C., and a plan from Bush's 2001 Social Security commission.

The federal 12.4 percent payroll tax is split between workers and employers. Workers could divert 4 percentage points, while the remaining 2.2 percentage points in taxes would continue going into the system.

Graham's plan calls for the annual contributions to be capped at $1,300, while the commission proposed a lower limit of $1,000.

To sell the idea of a Social Security overhaul - and private investment accounts - the administration plans to duplicate its successful campaign for tax cuts.

At an event planned for Monday, Bush will meet with White House-approved people of varying ages to illustrate how changes to Social Security would affect different generations.

The strategy is similar to Bush's efforts to gain support for his tax cut packages by featuring "tax families" and their financial situations.

"That's the model," said Michael Tanner, director of the Cato Institute's Project on Social Security Choice. The libertarian think tank has been a longtime proponent of investment accounts.

"This is the way the president tends to campaign on these issues," Tanner said, noting similar strategies for Bush's Medicare and education plans. "He hasn't lost one he wanted to win yet."

Cabinet officials are stepping up their roles in the effort. Treasury Secretary John Snow, Labor Secretary Elaine Chao and others can be expected to visit communities across the country to talk about Social Security.

--Leigh Strope