Marathon Petroleum 401(k) Plan
Officially: MARATHON PETROLEUM THRIFT PLAN
Marathon Petroleum Thrift Plan is the 401(k) plan for employees of Marathon Petroleum Company LP. The 2024 Form 5500 reports 27,613 participants with account balances and $8.33 billion in plan assets at year end. The plan is recordkept by Fidelity Investments Institutional and is a 401(k)(12) safe harbor design with automatic enrollment for newly hired and rehired employees effective April 8, 2024. Participants invest through a core menu of mutual funds, common collective trusts, a Fidelity Freedom Blend target-date series, a stable value fund, Marathon Petroleum company stock, and a Fidelity BrokerageLink self-directed brokerage window.
By Zac Murphy, CFA charterholder and CFP professional. Published June 9, 2026. Verified against Form 5500 plan year 2024.
Get a personalized look at your Marathon Petroleum 401(k) options
Not sure if you're getting the most out of your plan? Tell us a bit about your situation and we'll help you understand your options.
Fund lineup
Your plan includes Fidelity BrokerageLink
Fidelity BrokerageLink is a self-directed brokerage feature within your 401(k) plan. It lets you invest a portion of your 401(k) balance outside the standard fund menu, into individual stocks, ETFs, or a broader universe of mutual funds. BrokerageLink is a separate sleeve within your plan, but money held there remains inside your 401(k) and retains its tax treatment.
Who uses it
- Participants who want exposure beyond the plan's core menu, such as specific sector ETFs, individual stocks, or low-cost index funds not offered in the menu.
- Participants who want to consolidate the management of their 401(k) alongside other investment accounts.
- Participants with meaningful balances who want more direct control over allocation.
- Self-directed accounts can be actively managed by the participant directly, or by an advisor if the participant chooses to work with one.
Important considerations
- Additional costs. Brokerage windows often carry additional fees, and trading commissions vary by provider and security type.
- Allocation limits. Many plans cap the percentage of your balance that can be moved into the brokerage sleeve. Some require a minimum balance in the core menu.
- Plan rules still apply. Loan and distribution rules, vesting schedules, and contribution limits are unchanged. The brokerage window changes what you can invest in, not the underlying retirement account rules.
- Confirm details with your plan administrator. The specifics of your plan's brokerage window, including which securities are eligible and any account-level fees, are governed by your plan documents.
Why our allocations use only index funds
The actively managed funds in this plan cost more per year than the plan's index funds, which run roughly 0.02% to 0.06%. Decades of research on long-term active fund performance do not support reliable outperformance net of fees, which is why the allocation ideas below may consider using only the low-cost index options.
Employer match
Estimates assume a constant salary and the match formula shown above. Your actual match depends on your plan's exact terms.
The cost of contributing only --%
On a $60,000 salary, contributing just half the match threshold would leave about -- in employer match unclaimed each year. Invested over 20 years at a hypothetical 7% annual return, that forgone match could have grown to roughly -- (a hypothetical illustration, not a projection). The match is the highest-return contribution you will make all year.
Sources
- Plan metadata (employer, participants, assets, plan year): Form 5500 annual return/report, plan year 2024 -- view filing
- Summary Plan Description (SPD) and fee disclosure (404a-5), where available from the plan administrator.
This page is for educational purposes only and does not constitute investment, tax, or legal advice, nor a recommendation to buy or sell any security. Information is drawn from public Form 5500 filings and plan documents and may be incomplete or out of date. You may consider consulting a qualified professional and confirming all details with your plan administrator before making decisions. Waterfall Planning is not affiliated with Marathon Petroleum.
Find your risk profile
Answer 13 questions to see which allocation fits your situation.
Risk assessment methodology based on Grable, J. E., & Lytton, R. H. (1999). Financial risk tolerance revisited: The development of a risk assessment instrument. Financial Services Review, 8, 163-181.
Allocation ideas
Five sample mixes built from this plan's funds, from conservative to growth. Take the assessment above to see which one fits your risk profile.
Capital preservation with minimal market exposure, built from bonds and stable value.
Mostly bonds with a small stock sleeve for modest growth.
A classic 60/40 split of stocks and bonds.
Stock-heavy with a bond cushion for a long horizon.
All stocks for maximum long-term growth potential, with higher short-term volatility.
These allocation ideas are educational illustrations built from this plan's available funds and a standard risk-tolerance assessment. They are not personalized investment advice or a recommendation, and risk tolerance is only one factor in an investment decision. You may consider consulting a qualified professional before making changes to your account.