Retirement Plan Guide
The Largest 401(k) Plans in America
Based on 2024 DOL Form 5500 filings. Total plan assets at year-end 2024.
According to the U.S. Department of Labor's Employee Benefits Security Administration, the 2024 Form 5500 filings cover roughly 102,703 401(k) plans holding the bulk of America's $11.5 trillion in private retirement assets. The largest employer 401(k) plans reveal which companies offer the most substantial benefits: Boeing, IBM, Microsoft, and Bank of America rank among the top, several with more than $50 billion in plan assets. Scale matters, plans above $50 billion can negotiate fund expense ratios below 0.05%, a fraction of what the smallest plans pay. See our methodology for how these figures are read from each filing.
| # | Plan Name | Sponsor | Participants | Total Assets |
|---|---|---|---|---|
| 1 | The Boeing Company 401(k) Retirement Plan | The Boeing Co. and Consolidated Subsidiaries | 139,394 | $73.9B |
| 2 | Microsoft Corporation Savings Plus 401(k) Plan | Microsoft Corporation | 118,818 | $65.6B |
| 3 | The Bank of America 401(k) Plan | Bank of America Corporation | 168,963 | $62.9B |
| 4 | IBM 401(k) Plan | International Business Machines Corporation | 52,674 | $60.4B |
| 5 | Rtx Savings Plan | Rtx Corporation | 124,876 | $58.6B |
| 6 | JPMorgan Chase 401(k) Savings Plan | JPMorgan Chase Bank, National Association | 185,532 | $52.9B |
| 7 | Lockheed Martin Corporation Salaried Savings Plan | Lockheed Martin Corporation | 96,812 | $51.4B |
| 8 | Walmart 401(k) Plan | Walmart Inc. | 1,635,899 | $50.8B |
| 9 | Google LLC 401(k) Savings Plan | Google LLC | 116,712 | $48.7B |
| 10 | AT&T Retirement Savings Plan | AT&T Inc. | 109,889 | $43.1B |
| 11 | Costco 401(k) Retirement Plan | Costco Wholesale Corporation | 202,468 | $41.0B |
| 12 | Northrop Grumman Savings Plan | Northrop Grumman Corporation | 104,719 | $39.5B |
| 13 | Amazon 401(k) Plan | Amazon.Com Services, LLC | 1,209,303 | $34.6B |
| 14 | Fidelity Retirement Savings Plan | Fmr LLC | 66,907 | $34.2B |
| 15 | Oracle Corporation 401(k) Savings and Investment Plan | Oracle Corporation | 58,962 | $31.0B |
| 16 | CVS Health Future Fund 401(k) Plan | CVS Health Corporation | 240,493 | $30.1B |
| 17 | Verizon Savings Plan for Management Employees | Verizon Communications Inc. | 69,218 | $29.4B |
| 18 | Unitedhealth Group 401(k) Savings Plan | Unitedhealth Group Incorporated | 205,460 | $26.6B |
| 19 | Fedex Corporation Retirement Savings Plan | Fedex Corporation | 113,079 | $25.4B |
| 20 | Intel 401(k) Savings Plan | Intel Corporation | 55,298 | $24.9B |
What Makes a Large 401(k) Better?
- Lower fees - institutional funds in large plans often have expense ratios below 0.05%
- Better fund selection - access to institutional share classes not available to individuals
- Higher employer match potential - large companies often match more generously
Worked example: scale and expense ratio relationship
Industry-published Department of Labor analyses consistently show an inverse relationship between plan size and per-participant expense ratios. A plan with $500 million in assets typically operates with total expenses near 0.65% of assets, while a plan with $50 million operates closer to 1.15%, and a plan with $5 million closer to 1.55%. For a participant with $200,000 in the plan, the difference between 0.65% and 1.55% is $1,800/year in fee drag, or roughly $65,000 over a 25-year career when compounded. This is not a quality difference in investment selection; it is a fixed-cost spread across more participants. The largest plans simply have more shoulders to bear the cost of recordkeeping, audit, and compliance.
Comparative scale matrix
| Plan size tier | Typical expense ratio | Investment menu breadth |
|---|---|---|
| $1B+ (mega-plan) | 0.35% to 0.55% | 30 to 60 funds + brokerage window |
| $250M to $1B (large) | 0.55% to 0.85% | 20 to 35 funds |
| $50M to $250M (mid) | 0.85% to 1.20% | 15 to 25 funds |
| $10M to $50M (small) | 1.20% to 1.60% | 10 to 18 funds |
| Under $10M (micro) | 1.40% to 2.00% | 8 to 15 funds, often retail share classes |
A 100-basis-point expense gap compounded across a 30-year accumulation curve is the difference between retiring at 65 and retiring at 67, fees are not a footnote.
What the top-of-list plans tend to share
Across the largest 200 defined-contribution plans by participant count, several structural patterns recur. Most use an open-architecture recordkeeper that decouples investment selection from fund-management revenue. Most offer a tiered investment menu with target-date funds as default, a 12-to-20 fund core menu, and a self-directed brokerage window for engaged participants. Most disclose investment-only expense ratios at the fund level (separate from recordkeeping fees) so participants can see exactly what each line is costing. The largest plans also tend to commission independent annual fiduciary reviews from third-party investment consultants, these reviews are typically referenced in the plan's Schedule C disclosures on Form 5500. None of these features are required by ERISA, but they correlate with the lowest participant cost burden in the federal data.
