For better or for worse, 401(k) plans are the foundation of retirement savings for most Americans now. Other than Social Security benefits, 401(k) plans represent the bulk of financial assets available to people after they stop working.
The plans don't come with any guarantees and they don't manage themselves. These tax-advantaged accounts, however, are powerful tools to help people prepare for retirement.
"The 401(k) plan has become the dominant source of retirement savings for most Americans," said Andy Eschtruth, associate director at the Center for Retirement Research at Boston College. "When it comes to private savings, this is it."