Marius Stäcker

Strategic Advisor & Fractional / Interim Ceo / Coo / Cro

Chestnut Capital · Berlin, Germany

Present

Helping B2B tech companies navigate the high-stakes journey from €1M to €20M ARR. Chestnut Capital is my investment and advisory vehicle. After 15 years as a founder and operator, I partner with ambitious leadership teams, providing the strategic oversight and hands-on execution needed to scale. Core Offering: 🚀 Fractional & Interim Leadership: Stepping in as CEO, COO, or CRO to bridge leadership gaps or lead turnarounds. 📈 GTM Transformation: Professionalizing sales, marketing, and operations to unlock the next level of scale. 🛠️ Operational Excellence: Building the systems and culture required to lead teams of 200+ and reach 8-digit ARR. Investment Activity: Actively backing the next generation of AI-first B2B software. Portfolio includes... • Plato: AI-native OS | €20M+ (Atomico, Cherry) • Reonic: OS for Renewables | €15M+ (Northzone, Point Nine) • Vamo: Sustainable Heating | €10M+ (Extantia, GET Fund) | Secondary Exit • & others... 👉 Reach out via DM to discuss your journey.

Angel Investor & Advisor

Plato

Present

AI-native operating system for wholesale distribution. Raised more than €20M in funding by Atomico, Cherry Ventures and others.

Angel Investor & Advisor

Reonic

Present

Operating system for renewable energy installers. Raised more than €15M by Northzone, alongside Point Nine and others.

Ceo & Co-Founder

ToolTime · Berlin Area, Germany

As Co-Founder and CEO, I led ToolTime from its inception through its hyper-growth phase into a leading AI-native Cloud Operating System for trades businesses. Key Milestones: • Scale: Built the venture from 0 to 8-digit ARR with a team of 80+ professionals. • Funding: Raised €55M in total capital to digitize legacy workflows in the craftsman sector. • Product: Developed a full-stack SaaS solution automating invoicing and scheduling. Spearheaded the AI strategy to automate manual workflows and data entry for thousands of businesses. • Transition: Led the company through its scaling phase and successful leadership transition in early 2026.

Angel Investor & Advisor

Vamo

Heat pump scale-up for the green energy transition. Raised over €10M in funding by Extantia and GET Fund, resulting in a succesful secondary exit.

Venture Cro / Coo (Sr. Venture Architect)

BCG X · Berlin Area, Germany

Sr. Venture Architect at BCG X, the tech build and design unit of BCG (Boston Consulting Group). Worked on multiple digitalisation / strategy projects for large corporates. Project highlights: - Served as (interim) CRO/COO of a Fintech startup funded by a major German financial institution for a year. Build up the team from 0 to +30 employees and grow revenues from 0 to 7-digits. - Served as (interim) CRO for a B2B SaaS startup for 6 months. Joined during ideation and helped the company find product-market-fit.

Vp Revenue & Gm Dach

Movinga · Berlin Area, Germany

Vice President & Managing Director DACH at Movinga, a pan-European marketplace for the moving industry with over €80M in funding by i.a. Index Ventures, Earlybird, Rocket Internet / Global Founders Capital. Lead a team of 100 employees in Sales, Operations and Customer Care and held 8-digit € P&L responsibility.

Co-Founder & Ceo / Cro

Various Startups · Berlin, Germany

Gained invaluable entrepreneurial experience by co-founding four startups between 2011 and 2016. - In 2015, co-founded a bootstrapped direct-to-consumer brand called GET AMBER. The brand was taken over by a competitor in 2016. - Between 2013 and 2015, built up a marketplace for driving schools named Fahrschulvergleich as Co-Founder & CEO. Raised 7-digit funding and built up a team of 15 employees. The business was merged into CHECK24 in 2018. - In 2012, co-founded a digital printing business called Schooltique next to my studies. Operated the business as side-project for some time. - In 2011, initiated Germany's largest Facebook community at the time with more than 700k followers. Successfully sold the business two years later to an investor.

Country Manager

SumUp · Berlin Area, Germany

Founded in 2011, SumUp is a European fintech giant today with more than 4 million customers. Joined the company after their Series A. Served as Country Manager and spearheaded the launch of the Austrian market.

Strategy Consulting

Roland Berger · Frankfurt Am Main Area, Germany

Roland Berger is a leading strategy consulting firm from Germany. Joined the company for an internship and worked on the post-merger integration of two large financial institutions.