A decline in retirement wealth between older baby boomers and their younger Boomer counterparts has been expected due to the increase in Social Security's full retirement age and a shift from defined benefit to defined contribution plans. However, new research from the Center for Retirement Research at Boston College characterized the retirement wealth of late boomers as "surprisingly low."

Late boomers represent the first generation where workers could feasibly have spent their entire career covered by a 401(k) plan, and increasing 401(k) and IRA balances that were expected to offset the gap created by a decline in pension programs haven't materialized for this age group, the brief said. 

Late boomers weren't always behind in private retirement savings, according to the Survey of Consumer Finances (SCF), which has been conducted every three years since 1983.