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Refactor Capital

refactor.com · Burlingame, CA

“The most enduring companies are created by founders willing to commercialize real science and scale real systems. We focus on hard tech at the intersection of computation and physical sciences—aerospace, biotech, energy, materials—where technical execution is the moat.”

$1M – $2M
Check Size
Leads
Lead Tendency
$225M
AUM
~1 Week
Timeline
01Investment Thesis

The most enduring companies are created by founders willing to commercialize real science and scale real systems. We focus on hard tech at the intersection of computation and physical sciences—aerospace, biotech, energy, materials—where technical execution is the moat.

Exclusion Criteria

No consumer software, no incremental improvements, no non-technical founding teams, no companies that don't require real R&D.

02Investment Team
ZB
Zal Bilimoria
Founder & Managing Partner
KG
Katie Greenfield
Advisor
SS
Sara Sperling
Advisor
03F4 Research Brief

Refactor Capital Research

Investment Thesis

Refactor Capital invests in hard tech founders who are willing to commercialize real science and scale real systems. Founded by Zal Bilimoria (former a16z partner), the fund believes that the most enduring companies are created at the intersection of computation and the physical sciences. Rather than betting on incremental improvements, Refactor focuses on founders willing to tackle "hard but not impossible" problems across aerospace, biotech, energy, materials science, earth systems, and healthcare.

Zal's career trajectory—from building software at Microsoft, Google, Netflix, and LinkedIn, to joining a16z in 2013 where he helped lead the firm's earliest bio and health investments and supported the launch of a16z's first Bio Fund in 2015—has shaped Refactor's distinctive thesis. The fund operates as a first institutional partner to these technical founders as they transform R&D into category-defining products.

Sector Focus

Refactor Capital's portfolio spans multiple hard tech domains:

Biotech & Life Sciences: Cell and gene therapy manufacturing (64x), genomic sequencing (Gencove), drug discovery platforms (Octant, Parallel Bio, Epana), therapeutic delivery (Granza, Mythic), reproductive health (Vitra, YourChoice), novel therapies (Loyal for longevity in dogs, Adventris cancer therapies, Miist inhalable therapeutics).

Aerospace & Defense: Satellite operations (Astranis - Micro GEO satellites), advanced spacecraft (General Galactic), and defense applications (Pilgrim).

Energy & Climate: Energy storage (Lumindt solid-state systems, Pila backup batteries), nuclear energy (Hexium isotope enrichment), electric powertrains (Brelle), renewable energy (Thalo), and climate prediction (Causal AI weather modeling).

Critical Materials & Chemicals: Bio-based manufacturing (Solugen chemicals using biology, Aether enzymes, Macro Oceans kelp chemicals), synthetic biology (Berkeley Yeast, Phytoform crop genome editing), sustainable materials (Checkerspot algae-based), and chemical marketplaces (Knowde).

Healthcare Infrastructure: Digital pathology (PathAI), revenue cycle operations (AKASA), emergency department software (Vital), employer health plans (Curative), and telemedicine platforms (Ophelia, Lucy). Refactor also invests in consumer health applications like Headspace and mental health (Atlas wearables, Picnic health data).

Earth Systems: Parametric insurance (Floodbase), environmental remediation (Remedy bringing land online), and emissions reduction (Thalo).

Stage Focus & Check Size

Refactor operates at seed and pre-seed stages with a typical check size of $1-2M. Zal explicitly targets:

  • Pre-seed rounds with $1-2M checks
  • Seed rounds with $1-2M checks
  • 10% target ownership per investment
  • Occasional Series A follow-ons from reserves

The fund size ($50M for Fund 4, closed June 2024) suggests Zal manages approximately $1-2M checks per company, allowing meaningful ownership at these early stages.

Lead Tendency

Zal typically leads or co-leads pre-seed and seed rounds. Recent evidence from the portfolio shows he maintains active deal flow and syndication relationships. As a solo capitalist, decision-making is fast—he emphasizes being "on speed dial" for founders with direct, responsive access.

Recent Activity

2025 Investments (YTD):

  • Remedy Scientific (April 2025, Seed)
  • Miist Therapeutics (February 2025)
  • Pila Energy (October 2025, Seed, $4M round with R7 Partners lead and Toyota Ventures)

2024: Fund 4 launched in July 2024 with active deployment. Notable investments include various portfolio companies across the sectors listed above.

Fund Status: Fund 4 ($50M) is actively deploying. Zal has raised a new fund every few years historically and now manages $225M+ in assets under management across 4 funds.

Portfolio Highlights

Exits & Graduates:

  • Coinbase (cryptocurrency exchange, public $COIN)
  • Clover Health (Medicare Advantage, public $CLOV)
  • Betty Labs/Locker Room (acquired by Spotify $SPOT)
  • FactoryFour (acquired by Xometry $XMTR)
  • Blockfolio (crypto wallet, acquired by FTX)
  • Hero CRM (acquired by People.AI)
  • Able Health (acquired by Health Catalyst $HCAT)
  • Enzyme (FDA compliance, acquired by Roivant $ROIV)
  • Tempest (digital recovery, acquired by Monument)
  • Umbrella senior care (acquired by IAC)
  • ANA therapeutics (acquired by Neurobo $NRBO)
  • Uniform orthodontics (acquired by Impress Dental)
  • Avail surgery consults (acquired by Mendaera)
  • Kip mental health (acquired by Modern Health)

Active Portfolio: 50+ active companies across biotech, aerospace, energy, materials, and healthcare with strong momentum.

Team

Zal Bilimoria, Founder & Managing Partner: Background spans software engineering at Microsoft, Google, Netflix, and LinkedIn (2008-2013), followed by 3+ years at Andreessen Horowitz (2013-2016) leading early bio and health investments. Expertise in technical due diligence for physics/biology/chemistry-based companies. Solo capitalist structure means he makes all investment decisions personally.

Advisors: The fund leverages a network of advisors offering domain expertise across aerospace, biotech, energy, materials, and healthcare.

Decision Process & Timeline

Structure: Solo GP model. Zal makes all decisions personally, enabling fast decision-making without committee delays. Decision timeline is rapid—emphasizing responsiveness and founder accessibility.

Support Beyond Capital: Refactor founders receive:

  • CFO support for financial management
  • Communications training for fundraising and PR
  • Mental fitness programs for founder wellness
  • Access to Zal's personal network of advisors
  • Direct, responsive relationship with a seed-stage veteran

Geographic Focus

Primarily US-based with emphasis on companies that can scale nationally or globally.

Notable Positioning

From the website: "I invest in seed-stage hard tech companies primarily in the US... I typically lead or co-lead pre-seed and seed rounds with $1-2M checks... As a solo capitalist and the only employee at Refactor, I decide fast, and if we team up, you'll have me on speed dial. It's that simple. #BetterCallZal"

The branding ("Better Call Zal," play on "Better Call Saul") emphasizes accessibility and speed, differentiating from committee-based firms.

04Selected Portfolio
Aerospace & Defense
Astranis
AgTech & Agriculture
Fyto
Biotech & Life Sciences
Gencove·Loyalfordogs·Octant Bio·YourChoice Therapeutics·Miist·Parallel Bio·Adventris·Granza·Vitra Labs·Epana Bio·Aether Biomachines·PathAI·Onyx Bio
Climate & Sustainability
Remedy Scientific·Thalo Labs·Pila Energy
E-commerce & Marketplaces
Knowde
Energy & Power
LuminDT·Network Ocean·Hexium
Enterprise Software
64x·BBB·BioRender·The Biological Computing Co·Inferra·Causal Labs
Food & Beverage
Checkerspot·Macro Oceans·Berkeley Yeast·Lucy
Healthcare & Digital Health
Headspace·PicnicHealth·Ophelia·Vital·AKASA·Curative
Insurance
Floodbase·Kin
Manufacturing & Industrial
Solugen
Robotics & Automation
Mythic·Brelle
Security & Cybersecurity
Orchid
Travel & Hospitality
Pilgrim·Atlas
Other
Phytoform·Coinbase·General Galactic
Open the full portfolio→
05Recent Updates

Fresh signals from public announcements, essays, and portfolio activity.

See full activity (18) →
Refactor Capital invested in Inferra, an AI inference infrastructure company at the metro edge.
INVESTMENT·pitchbook.com
JUL 29, 2026
Refactor Capital announced Fund 5, a $50M seed-stage hard tech fund. 100% of Fund 5 came from existing LPs. Five funds, ten years, one employee.
NEW FUND·refactor.com
MAY 7, 2026
Closed Refactor Fund 5 at $50M, backed 100% by existing LPs. Five funds, ten years, one employee.
NEW FUND·refactor.com
MAY 7, 2026
Zal Bilimoria published a thesis essay on why 2026 is the most exciting time in a decade to back hard tech founders, and what Refactor looks for at the seed stage in aerospace, energy, bio, and critical materials.
ESSAY·refactor.com+1
APR 15, 2026
Zal articulates why 2026 is the most exciting time in a decade to back hard tech founders, covering Refactor's seed thesis across aerospace, energy, bio, and critical materials.
ESSAY·refactor.com
APR 15, 2026
06Frequent co-investors
BV
Breakout Ventures
Both backed 4 of the same companies
Vitra Labs, Epana Bio, Parallel Bio, Checkerspot
C
Cantos
Both backed 4 of the same companies
Remedy Scientific, Astranis, Solugen, Pilgrim
KV
KdT Ventures
Both backed 4 of the same companies
Solugen, Epana Bio, PathAI, Checkerspot
FY
Fifty Years
Both backed 3 of the same companies
Astranis, Solugen, BioRender
BF
Black Flag
Both backed 2 of the same companies
Astranis, Solugen
Find the investors for your round→
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Quick Reference
Check Size
$1M – $2M
Stages
Pre-Seed · Seed · Series A · Series B
AUM
$225M
Decision
Solo GP · ~1 Week
Warm Intro
Not Required
Involvement
Advisor
Location
Burlingame, CA
Sector Focus
Fintech & PaymentsAerospace & DefenseInsuranceBiotech & Life SciencesSemiconductors & HardwareLogistics & Supply ChainClimate & SustainabilityDeveloper Tools & InfrastructureEnergy & PowerHealthcare & Digital Health
Models
Hard TechBiotechAerospaceEnergyMaterials ScienceClimate Tech
Technology
AI/MLAdvanced ManufacturingSynthetic BiologyNuclear EnergySatellite Technology
See all Fintech & Payments investors →See all Aerospace & Defense investors →See all Insurance investors →
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Focus Areas
Fintech & PaymentsAerospace & DefenseInsuranceBiotech & Life SciencesSemiconductors & HardwareLogistics & Supply ChainClimate & SustainabilityDeveloper Tools & InfrastructureEnergy & PowerHealthcare & Digital Health

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F4 Intelligence Report · Last Researched October 1, 2026F4 Research Engine