Mercury Systems 401(k) Plan
Officially: MERCURY EMPLOYEES RETIREMENT INVESTMENT TRUST
The Mercury Employees Retirement Investment Trust is a 401(k) plan sponsored by Mercury Systems, Inc., serving 2,246 active participants and 1,094 inactive participants as of December 31, 2024. The plan held $475.6 million in assets at year end, with Fidelity Investments serving as the primary recordkeeper and trustee. The plan operates as a defined contribution plan with automatic enrollment, matching contributions at the discretion of each business unit, and offers a broad menu of mutual funds and collective investment trusts.
By Zac Murphy, CFA charterholder and CFP professional. Published June 12, 2026. Verified against Form 5500 plan year 2024.
Get a personalized look at your Mercury Systems 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
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
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 Information is drawn from public Form 5500 filings and plan documents and may be incomplete or out of date.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 Mercury Systems.
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.