How the Strüngmann Brothers Built Germany's Most Important Biotech Family Office
- Jörn Menninger
- 9 minutes ago
- 11 min read
What Is This About?
Andreas and Thomas Strüngmann are German identical-twin billionaires who built Hexal into Europe's largest generic-drug producer, sold it to Novartis in 2005 for €5.65 billion (~$7.5B cash), then anchored BioNTech in 2008 with a €136.5–180 million bet that peaked at over $50 billion in August 2021 and remains worth ~€10 billion today — the architect-class behind DACH biotech.
Most coverage of European deep tech ends with a sigh: Europe doesn't have the capital, the patience, or the founders. That story is wrong. Europe has all three — they just don't usually appear in the same room at the same time. When they do, the result is BioNTech. And underneath BioNTech, almost invisibly, is a single Munich family office holding the structural position that made the whole thing possible.
Andreas and Thomas Strüngmann are not household names outside Germany. They prefer it that way. But the brothers' four-decade arc — from inheriting a generics business in 1979, to founding Hexal in Holzkirchen with 22 employees in 1986, to selling Hexal+Eon Labs to Novartis for €5.65 billion cash in 2005, to anchoring BioNTech with €136.5 million in 2008, to a stake that peaked at over $50 billion in August 2021 and still sits at ~€10 billion today (BioNTech market cap ~€22.8B at €86/share, April 2026) — is the most consequential capital story in DACH biotech. It's the story this cluster is about.
This piece kicks off a four-part Strüngmann Cluster on Startuprad.io. It sits inside our broader Capital & Power in Startups pillar — the editorial spine for understanding how DACH money, founders, and networks actually shape the ecosystem.
Executive Summary
The Strüngmann brothers occupy a structural position in DACH biotech that has no real US equivalent: a single-family office with biotech expertise, four-decade horizons, and the willingness to anchor companies that public markets would have killed. Hexal funded Athos. Athos funded BioNTech. BioNTech (post-COVID) refunded Athos at a 550% gain. The compounding loop is the story — not any single deal.
Key Takeaways
The Strüngmann brothers built Hexal from 1986 (Holzkirchen, 22 employees) to 2005 (~7,000 employees, €1.11B revenue), sold to Novartis for €5.65 billion cash, and used the proceeds to seed Athos Service in Munich.
Their €136.5–180M anchor investment in BioNTech in 2008 peaked at over $50 billion in August 2021 when BioNTech's market cap exceeded $100B — one of the largest venture-style returns in European history. Stake currently ~43.5%, worth ~€10 billion (BioNTech ~€22.8B / €86 share, April 2026).
November 2023: brothers sold $110M in BioNTech shares with $220M more planned, recycling proceeds into the next generation of bets (Antheia, AAVantgarde Bio, AMSilk, Bambusa Therapeutics, Doctolib).
They operate through a four-vehicle structure: Santo Holding (Zug — primary holding), Athos Service / ATHOS KG (Munich — operational arm + holding entity), AT Impf GmbH (BioNTech SPV), ATS Beteiligungsverwaltung (Ganymed SPV). Thomas Maier is General Partner (Komplementär) of ATHOS KG per BioNTech's SEC Schedule 13G filing.
Their model is structurally different from US venture capital: no fund-life pressure, no exit timeline, no LP reporting cycle. That's the source of the edge.
Combined net worth April 2026: $23 billion ($11.5B each, Forbes real-time).
From Mülheim to Hexal: the inheritance the brothers built into a generics empire
Andreas and Thomas Strüngmann were born on 16 February 1950 in Mülheim an der Ruhr, North Rhine-Westphalia, to Ernst and Gisela Strüngmann. Their father Ernst founded Durachemie, a small generics company, in 1956. The family later relocated with the company to the Tegernsee area in Bavaria, where the brothers still live today. Andreas studied medicine at the University of Freiburg and the University at Buffalo, ultimately earning his M.D. Thomas earned his business degree at the University of Augsburg. Thomas became the public face; Andreas operated behind the scenes. By the brothers' own account, Andreas generates the ideas, Thomas executes them.
The brothers entered Durachemie in 1979. In 1986 they sold the family business to Merck KGaA for 100 million Deutschmarks (~$41M at 1986 exchange rates) — and immediately reinvested the proceeds into founding Hexal AG in Holzkirchen, Bavaria, with 22 employees. Same business model, different scale. They built the Salutas manufacturing plant in Barleben — one of Europe's most modern and automated pharmaceutical factories. By the early 2000s, Hexal was producing 5,900 different drugs and 200 million articles annually. Revenue hit €1.11 billion in 2003 and $1.65 billion in 2004, with ~7,000 employees worldwide by 2005.
The Novartis exit (Feb 2005): €5.65B cash, the world's largest generics company
On February 21, 2005, the Strüngmanns announced the sale of Hexal AG and their 67.7% controlling stake in Eon Labs to Novartis for a combined €5.65 billion (~$7.5B at the time). It was the largest private-company sale in German history at the time. Novartis integrated the businesses into its Sandoz division — instantly creating the world's largest generic-drug company, ahead of Teva and Mylan. Cost synergies of $200M per year were forecast within three years.
For the Strüngmanns, the 2005 exit ended the Hexal chapter and started everything else. Andreas reportedly bought a yacht. The brothers, then 55, didn't retire. They built a family office — and chose, in a testament to their lifelong partnership, not to split the proceeds.
The four-vehicle architecture: Santo, ATHOS KG, AT Impf, ATS
Coverage of the Strüngmann investments often confuses the structure. There are four primary vehicles, each with a distinct role:
Santo Holding GmbH — Zug, Switzerland-based primary holding company. The name is a contraction: Strüngmann Andreas Thomas → SAnTo. Diversified across biotech, healthcare, real estate, and adjacencies.
ATHOS KG — Munich-based limited-partnership family-office holding. Thomas Maier serves as General Partner (Komplementär) per BioNTech's SEC Schedule 13G filing. ATHOS KG is the sole member of AT Impf GmbH — meaning ATHOS KG is the beneficial owner of the BioNTech stake.
Athos Service GmbH — Munich-based operational arm. Handles deal sourcing, due diligence, and portfolio management. Julian Zachmann is identified in some sources as a Managing Partner here (registry confirmation pending). Distinct from ATHOS KG.
AT Impf GmbH — special-purpose vehicle for immunology investments ("AT" = Andreas + Thomas, "Impf" = vaccine). The structure that holds the BioNTech anchor — the BioNTech Schedule 13G filing confirms: "The sole member of AT Impf GmbH is ATHOS KG." AT Impf controlled approximately 50% of BioNTech at the company's October 2019 NASDAQ listing.
ATS Beteiligungsverwaltung GmbH — separate vehicle used for early-stage backing of Ganymed Pharmaceuticals.
BioNTech (2008–today): from €136.5M seed to a $50B+ peak and back to ~€10B
The BioNTech investment came from a relationship that began earlier. The Strüngmanns were the founding investors in Şahin and Türeci's first company, Ganymed Pharmaceuticals (2001), with their stake held through ATS Beteiligungsverwaltung GmbH (a separate SPV from AT Impf). Athos invested €150M across multiple Ganymed rounds; Astellas Pharma acquired Ganymed in October 2016 for €422 million upfront plus up to €860 million in milestones — total deal value up to €1.282 billion. The Ganymed relationship built the trust that funded BioNTech.
Şahin and Türeci founded BioNTech in Mainz in 2008. The Strüngmanns put in ~€136.5–180 million as the founding seed — through AT Impf and ATS Beteiligungsverwaltung, with co-investors joining over time (notably Dietmar Hopp's Dievini Hopp BioTech, a separate but converging family-office capital pool). One of the largest seed rounds in European biotech history. The brothers held through a decade of pre-revenue scientific work. They participated in the $325 million Series B in 2018. No quarterly earnings theater. No pressure to exit.
In 2019 the Gates Foundation invested ~$55M for HIV and tuberculosis programs — pre-COVID validation that the mRNA platform was infectious-disease-capable. In October 2019 BioNTech IPO'd on NASDAQ at $15/share, raising $150M at a $3.4B valuation. AT Impf controlled approximately 50% — a stake worth ~$1.7B at IPO. More than 10× return before COVID even began.
Then March 2020: the Pfizer partnership for COVID-19 vaccine. November 9, 2020: Phase 3 trial efficacy >90%. August 2021: BioNTech's market cap exceeded $100 billion. The Strüngmann stake was briefly worth over $50 billion — making the brothers among the top 20 wealthiest people on the planet. One of the largest venture-style returns of all time.
The pandemic subsided. The stock normalized. In November 2023 the brothers sold $110M in BioNTech shares with $220M more planned. They remain the company's largest shareholders with a stake of approximately 43.5%.
Where this lands in April 2026: BioNTech market cap ~€22.8B at €86/share. The Strüngmann ~43.5% stake is worth roughly €10 billion ($10.7B). That's still ~73× return on the original €136.5M seed — eighteen years in, after the peak has come and gone. And the partial divestments funded the next decade of bets (Antheia, AAVantgarde, AMSilk, Bambusa, Doctolib).
What this architecture actually looks like (and why US venture can't copy it)
Three structural features make the Strüngmann model work:
1. No fund life. Athos doesn't return capital to LPs in seven years. It doesn't return capital at all in the conventional sense — it recycles. The Hexal exit funded Athos. Athos anchored BioNTech. BioNTech (after IPO and COVID) refunded Athos at multiples. That capital is now funding Antheia ($56M Jun 2025 + $24M Jan 2026), AAVantgarde Bio's $141M Series B (Nov 2025), AMSilk (€52M / $61M Sep 2025), Bambusa Therapeutics (2025), Doctolib (secondary), and others. The loop is the asset.
2. Domain expertise that compounds. The brothers spent 19 years building Hexal. They didn't pivot from finance into biotech — they came up through the science. When a Şahin or a Türeci pitches them, they don't need to pattern-match against Silicon Valley founders. They evaluate the biology.
3. Editorial discretion about positioning. The Strüngmanns don't court coverage. Their family office's investments are reported by Family Office Hub, Bloomberg, and Forbes — not press-released by the brothers. That low public profile is itself a moat: founders who want patient capital without media pressure self-select toward Athos.
The result: a single Munich family office occupies the anchor-investor position in companies (BioNTech, Immatics, Tubulis, Formycon, AAVantgarde Bio, Antheia, AMSilk, Bambusa Therapeutics) that, between them, define the next decade of European mRNA, oncology, gene therapy, biosimilars, and synthetic biology. Their philanthropy reinforces the founder pipeline: the Ernst Strüngmann Institute (ESI) in Frankfurt (a neuroscience research center partnered with the Max Planck Society), the Andreas & Susan Strüngmann Foundation (South African education, founded 2007), the €100,000 Strüngmann Award for DACH biotech entrepreneurs, and a €25 million / 10-year commitment to UnternehmerTUM and the TUM Venture Labs — Munich's two anchor families (Klatten + Strüngmann) converging on the same ecosystem player.
This cluster will spend the next three days unpacking how the model works and where it goes next. Tomorrow: the Hexal exit playbook — what the 2005 Novartis deal taught the brothers about patient capital. Sunday: Athos as model — why family-office capital out-patients venture capital, and how the Strüngmanns have converged with Susanne Klatten on the same Munich ecosystem player. Monday: Beyond BioNTech — what's actually in the Athos portfolio in 2026 and where the next decade goes.
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Frequently Asked Questions
Who are Andreas and Thomas Strüngmann?
German identical-twin billionaires born on 16 February 1950 in Mülheim an der Ruhr; the family later moved to Tegernsee, Bavaria, where the brothers still live today. They built and sold Hexal AG (and Eon Labs) to Novartis in February 2005 for €5.65 billion (~$7.5B) cash, then anchored BioNTech in 2008. Combined net worth $23 billion ($11.5B each) — Forbes real-time, April 2026. They operate through Santo Holding (Zug, Switzerland), ATHOS KG / Athos Service (Munich, Germany), and special-purpose vehicles AT Impf and ATS Beteiligungsverwaltung.
How much did the Strüngmanns invest in BioNTech?
~€136.5–180 million as founding seed in 2008 (the range reflects different aggregations across sources). They participated in the $325M Series B in 2018. At the October 2019 NASDAQ IPO ($15/share, $3.4B valuation) the brothers controlled approximately 50%, worth ~$1.7B. Stake peaked at over $50 billion in August 2021 when BioNTech market cap exceeded $100B. November 2023: sold $110M with $220M more planned. Current stake ~43.5%, worth ~€10 billion at BioNTech's April 2026 valuation (~€22.8B / €86 share).
Why did the Strüngmanns sell Hexal in 2005?
Discipline. Generics consolidation was peaking in 2005, premium multiples were available, and the brothers correctly anticipated that the consolidation premium would compress within a few years. They sold at the top of the cycle, not the top of the company — and took cash (not Novartis stock) for full optionality, which became the BioNTech anchor three years later.
What is Athos Service?
The Munich-based operational arm of the Strüngmann family-office structure. ATHOS KG sits above it as the Limited-Partnership holding entity (with Thomas Maier as Komplementär per BioNTech's SEC Schedule 13G); Santo Holding (Zug) is the broader diversified vehicle. Athos handles biotech and life-sciences portfolio management — currently anchoring BioNTech (~43.5%), Formycon (26.6%), Immatics, Tubulis, plus 2025-2026 deals in Antheia, AAVantgarde Bio, AMSilk, and Bambusa Therapeutics.
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About the Author
Joern "Joe" Menninger is the founder of Startuprad.io, Europe's leading English-language startup media platform covering the DACH region. With 740+ podcast episodes and over 1 million annual streams, Startuprad.io connects founders, investors, and corporate innovators across Germany, Austria, and Switzerland. Connect on LinkedIn.
Sources
Entities
Andreas Strüngmann
→ co_founded → Hexal AG (1986)
→ co_acquired → Eon Labs (1995)
→ exited_to → Novartis (Feb 2005, ~€5.65B cash)
→ co_controls → ATHOS KG (Munich) + Santo Holding (Zug)
→ anchor_investor_in → BioNTech (since 2008, via AT Impf)
→ born → 16 February 1950, Mülheim an der Ruhr
→ medical training → University of Freiburg + University of Buffalo (M.D.)
→ behind-the-scenes operator role
Thomas Strüngmann
→ co_founded → Hexal AG (1986)
→ co_acquired → Eon Labs (1995)
→ exited_to → Novartis (Feb 2005)
→ co_controls → ATHOS KG + Santo Holding
→ anchor_investor_in → BioNTech (since 2008)
→ business training → University of Augsburg
→ public face of the partnership
→ Forbes net worth: ~$11.5B (April 2026)
ATHOS KG
→ founded by → Strüngmann brothers
→ headquartered in → Munich, Germany
→ vehicle type → limited-partnership family-office holding
→ general partner (Komplementär) → Thomas Maier
→ controls → AT Impf GmbH (sole member)
→ source: BioNTech Schedule 13G filing (Tier 1)
Athos Service GmbH
→ part of → ATHOS KG family-office structure
→ headquartered in → Munich, Germany
→ role → operational arm: deal sourcing, due diligence, portfolio management
→ holds → BioNTech anchor (via AT Impf), Immatics, Tubulis, Formycon (~26.6%, €650M deal)
→ recent (2025-2026) → Antheia, AAVantgarde Bio, AMSilk (with AT Newtec), Bambusa Therapeutics, Doctolib
→ ecosystem commitment → €25M / 10 years to UnternehmerTUM + TUM Venture Labs
Santo Holding GmbH
→ co_controlled by → Strüngmann brothers
→ headquartered in → Zug, Switzerland
→ name origin → Strüngmann Andreas Thomas → SAnTo
→ vehicle type → broader diversified holding
→ historical: Santo Holding (Deutschland) GmbH held majority Eon Labs stake pre-2005
AT Impf GmbH
→ purpose → BioNTech-stake special-purpose vehicle
→ sole member → ATHOS KG (per BioNTech Schedule 13G)
→ controlled at IPO → ~50% of BioNTech (Oct 2019, NASDAQ)
→ current → ~43-44% BioNTech stake
ATS Beteiligungsverwaltung GmbH
→ purpose → Ganymed Pharmaceuticals SPV
→ pre-2016 → largest shareholder of Ganymed
Hexal AG
→ founded by → Strüngmann brothers (Holzkirchen, Bavaria, 1986, 22 employees)
→ scale → ~7,000 employees by 2005, €1.11B revenue 2003
→ exited to → Novartis (Feb 2005, integrated into Sandoz)
Novartis
→ acquired → Hexal AG + Eon Labs (Feb 2005, €5.65B / ~$7.5B)
→ integrated → Sandoz (became world's largest generic-drug company)
BioNTech
→ founded by → Şahin + Türeci + Huber (Mainz, 2008)
→ anchor investor → Strüngmann brothers / ATHOS KG / AT Impf (€136.5–180M seed)
→ pre-COVID validator → Gates Foundation ($55M, 2019)
→ commercial scale partner → Pfizer (COVID-19 vaccine, 2020+)
→ market cap peak → >$100B (Aug 2021); Strüngmann stake worth >$50B
→ market cap today → ~€22.8B at €86/share (April 2026); Strüngmann stake ~€10B
Strüngmann Award
→ founded by → Andreas + Thomas Strüngmann
→ prize → €100,000 for biotech entrepreneurs in DACH
Ernst Strüngmann Institute (ESI)
→ founded by → Strüngmann brothers (named for father Ernst)
→ headquartered in → Frankfurt, Germany
→ partnered with → Max Planck Society
→ focus → neuroscience research
Andreas & Susan Strüngmann Foundation
→ founded → 2007
→ founders → Andreas Strüngmann + Susan Strüngmann
→ focus → educational + community programs in South Africa (Western Cape)