Though millions of US workers have 401(k) plans, few studies evaluate participant investment performance. Using data on over 1,000 401(k) plans and their participants, we identify key portfolio investment inefficiencies and attribute them to offered investment menus versus individual portfolio...

Few previous studies have explored whether defined contribution retirement saving plans offer sufficiently diversified investment menus, though it is likely that these menus significantly shape workers' accumulations of retirement wealth. This paper assesses the efficiency and performance of...