Mark VC Research
Investment Thesis
Mark VC is an early-stage venture capital firm based in Austin, Texas, founded by Adam Zeplain and Andy Bursten. The firm takes a distinctly founder-centric approach to investing, with Zeplain known for conducting deep behavioral due diligence on founders before making investment decisions. Rather than focusing solely on market size, revenue metrics, or technology differentiation, Zeplain builds what Fortune described as a '360-degree behavioral map' of each founder — calling childhood friends, spouses, former colleagues, and mentors to understand the whole person.
While Mark VC describes itself as opportunistic and invests across a wide range of industries, the firm has particular strength in security & defense, healthcare, consumer technology, and enterprise software. Their tagline — 'We always look for ways to leave our mark' — reflects their commitment to being the most valuable investor on their portfolio companies' cap tables through hands-on operational support and coaching.
Stage Focus
Mark VC focuses on early-stage investments. Based on their portfolio composition, they invest primarily at Seed and Series A stages, though they have made select investments at later stages in high-conviction opportunities. The Anduril Series A investment at a $261M valuation and the Apptronik investment at a $250M post-money valuation demonstrate their ability to deploy meaningful capital into early-stage rounds for category-defining companies.
Check Size
Exact check sizes are not publicly disclosed. Based on the early-stage focus and portfolio mix of both emerging startups and breakout companies, estimated typical check sizes range from $500K to $5M for initial investments, with the ability to participate in larger rounds for high-conviction deals.
Lead Tendency
Mark VC appears to both lead and follow rounds, depending on the opportunity. Given Zeplain's deep diligence process and hands-on involvement, the firm likely leads or co-leads many of their early-stage investments while participating in larger rounds alongside other firms.
Recent Activity
According to PitchBook, Mark VC's latest investment was in Apptronik in February 2026. Tracxn reports the firm has invested in 36 companies total, with 1 new investment in the last 12 months as of November 2025. The firm appears to be actively deploying capital but at a measured pace, consistent with their deep-diligence approach.
Apptronik, a humanoid robotics startup that Mark VC invested in at a $250M valuation, has since grown to a $5B+ valuation — representing a significant recent success for the firm.
Portfolio Highlights
Mark VC has an impressive track record of backing category leaders:
Notable Exits/Public Companies:
- CrowdStrike (NASDAQ: CRWD) — cybersecurity leader, backed early
- Ring — acquired by Amazon
- Reddit — went public
- Bird (NYSE: BRDS) — electric scooters
Current High-Profile Portfolio:
- Anduril — defense technology, valued at $28B+ (Series A investor)
- Apptronik — humanoid robotics, valued at $5B+ (early investor)
- Andela — valued at $1.65B, connecting African developers with global companies
- Dragos — industrial cybersecurity leader
- Capella Space — satellite imaging
- ZenBusiness — business formation platform
Other Portfolio Companies:
- data.world — enterprise data catalog
- SafeGraph — geospatial data
- LivePerson — conversational AI
- Sana Benefits — health insurance
- Standard Metrics — investor reporting
- Full Harvest — B2B food marketplace
- Jona Health — gut health diagnostics
- Ostro Health — virtual specialty care
- Atropos Health — clinical evidence generation
- Seed — microbiome health
- Arch Labs — undisclosed
- Cellular Intelligence — undisclosed
- Conflixis — undisclosed
- OJO Labs — real estate technology
Team
Adam Zeplain, Co-Founder & Managing Partner: Born and raised in Houston, moved to Austin at 18. Started as an undergraduate intern at an Austin VC firm, then gained operating experience at Bazaarvoice (founded by Brett Hurt). Known for his deeply psychological founder diligence process and coaching approach. Featured in Forbes ('Austin's Best Kept Venture Capitalist') and Fortune. Close relationships with Jim Breyer, Dmitri Alperovitch (CrowdStrike co-founder), and other prominent tech figures.
Andy Bursten, Co-Founder: Serial operator and entrepreneur. Former Chairman of CyrusOne (data center provider, sold to ABRY Partners in 2007). Co-Founder and President of Coastal Telephone Company (sold to Eclipse Telecommunications/IXC Communications in 1999). Active board member across multiple organizations.
Cody Rapp, Partner, Operations & Strategy: Runs day-to-day fund operations and works closely with Zeplain on investment decisions. Previously Operating Partner (North America) at BBRC Private Equity and Co-Founder/Managing Partner at BBRC Labs within Brett Blundy's family office. Former Entrepreneur-in-Residence at PHD Ventures (Peter Diamandis), where he co-founded the 'Strike Force' incubator that birthed Bold Capital Partners ($500M+ VC fund).
Decision Process
Mark VC operates as a small partnership. Adam Zeplain drives investment decisions with input from Cody Rapp and Andy Bursten. Zeplain's diligence process is uniquely thorough — he conducts what he calls a full behavioral assessment, speaking with references from all stages of a founder's life including family, childhood friends, and former colleagues. This process is systematic but personalized to each founder.
Founder Preferences
Zeplain explicitly values founders with integrity, resilience, and operational excellence. He prioritizes understanding the whole person — their values, motivations, and interpersonal dynamics — over pure business metrics. He looks for founders who are coachable and open to deep personal engagement. The firm's approach suggests a strong preference for founders building in spaces they have deep personal conviction about.
Geographic Focus
Mark VC is based in Austin, Texas and invests primarily in US-based companies. The portfolio is distributed across major US tech hubs with a notable concentration in Austin-based companies.