Core Insights - A healthy-looking 401(k) balance may be shrinking in real terms due to structural issues within the account that often go unnoticed until significant damage has occurred [2] Group 1: Fees and Costs - The benchmark for low-cost index investing is nearly zero, with examples like the iShares Core S&P 500 ETF (IVV) charging an expense ratio of 0.03%. If a 401(k) holds index-style funds with fees over 0.5%, account holders are paying excessively for similar market exposure [3][7] - A $100,000 investment at a 7% gross annual return can grow significantly over 20 years at near-zero fees, while a 1% expense ratio can substantially reduce that outcome, leading to a widening gap in returns [4] Group 2: Fund Management - Actively managed funds typically charge higher fees and most underperform their benchmark indexes after fees over long periods. A 401(k) plan dominated by funds labeled with terms like "Growth" or "Opportunity" rather than "Index" may be steering participants toward higher-cost products [5] Group 3: Default Options - Employees who do not actively choose investments are placed in default funds, often target-date funds. With the federal funds rate at 3.75% and declining money market yields, remaining in a low-yielding default option while equity markets perform well can be a costly decision for retirement savers [6] Group 4: Structural Problems - Many 401(k) account holders unknowingly lose wealth due to structural issues such as excessive fees, concentrated employer stock positions exceeding 10%, drift from target allocations, and failure to rebalance, which can cost participants tens of thousands in lost compounding [7]