Plan Design Decisions Can Reduce Overconcentration in Company Stock Research from Vanguard supports the continuation of rethinking decisions about company stock offerings in defined contribution plans. Reported by A recent analysis from Vanguard explores the gradual abandonment of company stock in defined contribution (DC) plans. In the report, “Company Stock in DC Plans,” authors John A. Lamancusa and Jean A. Young note that at the time the Employee Retirement Income Security Act (ERISA) was adopted, defined benefit (DB) plans were the dominant type of retirement savings plan in America. ERISA imposed a 10% limit on company stock holdings in DB plans; however, no comparable company stock restriction was imposed on DC plans.