J2 Ventures

What J2 Ventures does

J2 Ventures is a Boston-based, early-stage venture capital firm founded in 2021 by Alexander Harstrick and Jonathan Bronson that invests in dual-use technologies with both commercial and U.S. national-security applications. The firm targets Seed and Series A rounds across four pillars: advanced computing, biomedical engineering, cybersecurity, and infrastructure. Its current and historical funds (~$52M in 2021, ~$69M in 2022, $150M in July 2024, and a $250M oversubscribed Brookhaven Fund in November 2025) have backed more than 30 portfolio companies, including Aalyria (space-based laser communications, $1.3B valuation), Code Metal (AI code translation, $1.25B valuation), Oura Ring, MesaQuantum, Phoenix Semiconductor, Principal Mineral, Aether Biomedical, Empress Therapeutics, Druid, Apex Space, and Parallel Fluidics.

The firm's revenue model is standard for an early-stage venture manager: management fees on committed or invested capital (typically around 2% annually on actively investing funds) plus carried interest on realized profits. Limited partners span institutional and family-office categories, including JP Morgan, MetLife, the State Investment Council of New Mexico, Upsher Management, and Alpha Leonis Partners. The team and advisor bench comprise PhD scientists, combat veterans, practicing physicians, and former Defense Innovation Unit, military, and federal-government leaders (including a retired Army Surgeon General and a retired Navy Vice Admiral), providing portfolio companies with strategic counsel and access to government/defense customers.

The core product offering is the Brookhaven Fund, a $250M oversubscribed vehicle dedicated to early-stage dual-use technology. The firm's value proposition centers on three pillars: government and defense network access, operational and scientific expertise, and capital efficiency through focused Seed/Series A investment. Geographic focus is the United States, with Boston as the operational headquarters and notable portfolio activity in supply-chain resilience (semiconductors, critical minerals, space-based communications) for U.S. national security.

Name

J2 Ventures

Legal name

J2 Ventures

Website

https://j2vp.com

Company type

Private

Founded year

2021

Operating status

Operating

Headcount range

1–10 employees

Short description

J2 Ventures is a Boston-based early-stage venture capital firm investing in dual-use technologies across advanced computing, biomedical engineering, cybersecurity, and infrastructure for both commercial and U.S. national security markets.

Ownership category

akta.pro rank

Product category

Venture Capital / Private Equity

NAICS

Portfolio Management and Investment Advice (52394), Other Investment Pools and Funds (5259)

SIC

Investment Advice (6282)

akta.pro primary industry

Early-Stage Venture Capital (Series A/B) (FSANAAAB)

akta.pro secondary industry

Late-Stage Venture Capital (Series C+) (FSANAAAC)

Keywords

• Venture capital investing
• Dual-use technology
• Early-stage startups
• Defense and national security
• Seed and series A

Headquarters

HQ city

Boston

HQ country

United States

HQ region

North America

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Not disclosed: No revenue model information available in the provided source data.

Go-to-market motion1 record

Core offering

J2 Ventures is a venture capital firm that manages and deploys investment funds into early-stage dual-use technology companies serving both commercial markets and U.S. national security. Its flagship offering is the $250 million oversubscribed Brookhaven Fund, investing at Seed and Series A across advanced computing, biomedical engineering, cybersecurity, and infrastructure. Portfolio companies receive capital, strategic counsel, and direct access to government and defense networks through the firm's team of PhD scientists, combat veterans, practicing physicians, and former Defense Innovation Unit leadership.

Product overview

J2 Ventures is a venture capital firm — not a software product company — whose primary offering is the Brookhaven Fund, a $250 million oversubscribed investment vehicle dedicated to early-stage dual-use technology serving both commercial markets and U.S. national security, with prior funds including a $150 million dual-use fund closed in 2024. The firm invests primarily in Seed and Series A rounds across four focus areas: Advanced Computing (e.g., Aalyria for space-based laser communications, Code Metal for AI code translation, Femtosense for edge AI, Paravision for computer vision, VectorWave for edge computing, MesaQuantum for quantum sensing), Biomedical Engineering (e.g., Aether Biomedical, Empress Therapeutics, Lumia Health, Parallel Fluidics, Safi Biotherapeutics, Oura Ring, Tasso, Sealonix, Micron Biomedical, Somnair), Cybersecurity (e.g., Acalvio, Cinder, iCOUNTER, Kusari, Musubi, Nametag, Redcoat AI, Unit 221B), and Infrastructure (e.g., Aalyria, Apex Space, Arkenstone Defense, Druid, InfiniG, LightSource, Plato Systems, Principal Mineral, Ravn, SkyFi). The firm's value proposition centers on providing founders with strategic counsel, government and defense sector access, and operational expertise drawn from a team of PhD scientists, combat veterans, practicing physicians, and successful entrepreneurs.

Differentiator

Problem solved

Functional benefit

Brands

• Brookhaven Fund: J2 Ventures' third fund, a $250M oversubscribed fund dedicated to dual-use technology investing for U.S. national security and commercial markets.

Products and services

• Brookhaven Fund J2 Ventures' $250 million oversubscribed flagship venture capital fund dedicated to early-stage dual-use technology serving both commercial markets and U.S. national security. Targets Seed and Series A rounds across AI, cybersecurity, healthcare, and infrastructure.
• J2 Ventures Dual-Use Investment Fund Prior $150 million venture capital fund focused on dual-use technologies serving civilian and government applications, with emphasis on military healthcare, supporting founders across Seed and Series A rounds.

Segments1 record

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Recent moves5 records

Expansion highlights5 records

Broad incumbents

• In-Q-Tel: Strategic, not-for-profit investor for the U.S. intelligence community, deploying capital into dual-use startups. Comparable in national-security thesis but funded as a strategic vehicle rather than a traditional VC.
• Founders Fund: Peter Thiel's venture firm with a long-standing focus on defense, space, and government-tech investments (Anduril, Palantir). Comparable defense-tech orientation but operates at multi-billion-dollar fund scale.
• Andreessen Horowitz (a16z) — American Dynamism: Mega-fund's dedicated defense/manufacturing/infrastructure vertical investing in dual-use startups. Overlaps with J2's thesis at a much larger scale and broader mandate.
• Lux Capital: Larger, established venture firm investing in frontier science and tech, with a notable defense-tech allocation. Comparable in dual-use thesis but operates across broader sectors and at significantly larger fund sizes.
• B Capital: Global venture firm with a dedicated aerospace and defense practice. Comparable in dual-use tech orientation at later stages than J2's typical Seed/Series A sweet spot.
• General Catalyst: Large multi-stage venture firm with an active defense and government-tech practice (Heliogen, Vannevar Labs). Overlaps with J2 in dual-use Seed/Series A but is a generalist with a much larger fund.
• Khosla Ventures: Large venture firm with selective frontier-tech and dual-use exposure. Overlaps with J2 on technology themes (AI, bio, infrastructure) but as part of a much broader generalist portfolio.

Direct peers

• Shield Capital: Early-stage venture firm focused on dual-use commercial and national security technology. Most directly comparable peer to J2 — similar Seed/Series A stage, similar defense-tech thesis, and overlapping portfolio (co-invested in Code Metal).
• Overmatch Ventures: Venture firm investing in defense and dual-use technology startups at the early stages. Closely comparable to J2 in fund size, stage focus, and co-investment activity (e.g., Principal Mineral, Code Metal).

Others

• Lockheed Martin Ventures: Corporate venture arm of Lockheed Martin investing in dual-use technologies that align with defense prime priorities. Related ecosystem participant, providing strategic capital and procurement pathways similar to those J2 brokers for portfolio companies.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/j2venturesusa

Revenue estimate

Valuation estimate

Number of profiles

Profiles15 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments54 records

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about J2 Ventures