Mainstem LLC
Rockville, MD Doing business as Blacklynx Services Part of Blacklynx, Inc.
- UEI
- SXHHGF88NPK4
- CAGE
- 63EE4
- Primary NAICS
- 541330 Engineering Services
- SAM.gov registration
- Active through
Company facts
- Self-certified in SAM.gov
- Entity structure
- Corporate Entity (Not Tax Exempt)
- NAICS codes registered in SAM.gov
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- 541330 Engineering Services Primary
- 334111 Electronic Computer Manufacturing
- 334112 Computer Storage Device Manufacturing
- 334118 Computer Terminal and Other Computer Peripheral Equipment Manufacturing
- 423430 Computer and Computer Peripheral Equipment and Software Merchant Wholesalers
- 513210 Software Publishers
- 518210 Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services
- 541511 Custom Computer Programming Services
- Corporate family
-
-
Blacklynx, Inc.
Parent
U9N2F4EATHX7
- Mainstem LLC SXHHGF88NPK4
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Blacklynx, Inc.
Parent
U9N2F4EATHX7
- SAM.gov registration date
- Physical address
- 51 Monroe St, Rockville, MD 20850, USA
- Website
- jacobs.com
- Founded
- 1947
- Employees
- 50K-100K
- Estimated annual revenue
- $10B+
- Industry
-
- Industrials
- Capital Goods
- Construction & Engineering
- Civil Engineering
- SIC code
- 87 Engineering & Management Services
- Profiles
Registration and certifications come from SAM.gov and the SBA; company details from public web sources. Updated .
Recent federal awards
| Award | Agency | Obligated | Awarded |
|---|---|---|---|
| Scalable homeland innovative enterprise layered defense (shield) initial order. | Missile Defense Agency | $500 | |
| Hulka II | Secretary of the Air Force | $564,289 | |
| C3PO support | Secretary of the Air Force | $2,498,846 | |
| Scampi II | Secretary of the Air Force | $7,475,000 | |
| Cabis providence award | Secretary of the Air Force | $4,448,803 |
About Mainstem LLC
Mainstem LLC, operating as Blacklynx Services, is a subsidiary of Jacobs Engineering Group Inc. that delivers defense systems engineering, AI data readiness services, and technical professional services to the Department of Defense as a prime contractor, competing full-and-open without set-asides across the Air Force, Navy, Missile Defense Agency, and Office of the Secretary of Defense.
Blacklynx Services is a for-profit limited liability company headquartered in Rockville, Maryland, with primary work in two NAICS categories: All Other Professional, Scientific, and Technical Services (11 awards) and Research and Development in the Physical, Engineering, and Life Sciences (5 awards), supported by secondary PSC coding in Support–Professional: Engineering/Technical (10 awards). The company operates exclusively as a prime contractor (19 awards, 100% of portfolio) and does not subcontract or pursue set-aside categories. Recent awards span defense R&D, systems modernization, and AI/data engineering across multiple classification levels and facility clearances.
Customer concentration is heavily skewed by vehicle structure. The top five funding entities by award count account for 74% of awards but only a fraction of combined potential value; the inversion reflects two massive IDIQs anchoring the portfolio. The Department of the Air Force Headquarters Secretary of the Air Force holds the largest count (8 awards, $23.5 million combined potential value), followed by the Air Force Materiel Command Research Laboratory (2 awards, $214 thousand). The Office of the Secretary of Defense, by dollars alone, commands the portfolio with a single $249 million Basic Ordering Agreement for AI data readiness support services running through March 2027, which has generated over $36 million in delivery orders since 2022. The Missile Defense Agency awarded Blacklynx a multi-billion-dollar ceiling Indefinite Delivery Indefinite Quantity vehicle on December 29, 2025 — the Scalable Homeland Innovative Enterprise Layered Defense (SHIELD) contract with a $151 billion ceiling and ultimate completion date of December 28, 2035 — carrying an initial delivery order of $500. The SHIELD vehicle procures research, development, prototyping, disruptive technologies, systems engineering, weapon design, production, test and evaluation, and modernization for multi-domain missile defense across all phases of flight.
Blacklynx places task orders under two named parent vehicles: an Air Force Indefinite Delivery Contract (FA714621DB001) supporting nine task orders valued at $24.1 million combined, primarily for CABIS, SCAMPI II, C3PO, and ANSWER programs, and the SHIELD IDIQ with one initial delivery order. Service Contract Inventory data shows minimal SCI-reportable federal services activity — $1 million invoiced in FY2023 across 1.3 FTEs — indicating the vendor's federal work concentrates on capital-intensive R&D and systems engineering delivery orders rather than labor-hour services contracts above the $150,000 threshold. Government-paid rates on SCI-reportable contracts ran at a median of $204.46/hr. Activity grew from two awards in 2020 to seven in 2022, then contracted to one award in 2023 before resuming with two awards in 2025, reflecting the lumpiness of large vehicle awards. Combined potential value across all 19 awards stands at $280.1 million, with combined dollars obligated at $26.4 million (9% of potential value), a marker of newly awarded vehicles with task-order-driven revenue realization ahead. As a Jacobs subsidiary, Blacklynx Services operates within a parent corporation that carries its own substantial federal prime and grant portfolio, enabling teaming and subcontracting relationships with larger Jacobs entities on complex defense modernization and homeland security programs.
Contract vehicles
Quick answers
What is Mainstem LLC's UEI?
Mainstem LLC's Unique Entity ID (UEI) in SAM.gov is SXHHGF88NPK4.
What is Mainstem LLC's CAGE code?
Mainstem LLC's CAGE code is 63EE4.
What is Mainstem LLC's primary NAICS code?
Mainstem LLC's primary NAICS code is 541330 (Engineering Services).
Where is Mainstem LLC located?
Mainstem LLC's physical address in SAM.gov is 51 Monroe St, Rockville, MD 20850, USA.
Is Mainstem LLC registered in SAM.gov?
Yes. Mainstem LLC's SAM.gov registration is active through August 18, 2027.
Who is Mainstem LLC's parent company?
Mainstem LLC is part of Blacklynx, Inc.
Which contract vehicles does Mainstem LLC hold?
Mainstem LLC holds a place on 2 federal contract vehicles, including MAS and SHIELD.
What is Mainstem LLC's most recent federal award?
Mainstem LLC's most recent federal contract award is Scalable homeland innovative enterprise layered defense (shield) initial order (HQ085926FF036), from Missile Defense Agency, on December 29, 2025.
On GovTribe
See Mainstem LLC's full federal record
- Federal contract awards
- IDV awards
- Contract vehicles
- Funding analysis by agency, NAICS and set-aside
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