Managed accounts are rapidly becoming a centerpiece of the modern 401(k). Fidelity data shows that access to the once-niche service has surged from 17% of plans in 2014 to 42% by 2023, reflecting a massive push by plan sponsors to offer personalization at scale. Yet, as adoption grows, a central question remains: Does the personalization alpha justify the added cost for the average saver? New research from Morningstar's Center for Retirement & Policy Studies offers an answer. Using a sophisticated new m ...