YK Bioventures Research
Investment Thesis
YK Bioventures is an early-stage biotech venture firm based in Burlingame, California, founded in 2022 by Gary Yeung and Mitch Kossar. The firm's public positioning is "Beyond Capital": rather than acting as a passive check-writer, YK Bioventures frames its core value as deep-rooted industry operating experience and high-level connections that help translate breakthrough academic and clinical research into durable companies. The founders describe themselves as "serial builders" who have previously founded and scaled multiple biotech ventures, and the firm is backed by a group of industry executives and Wall Street investors. Notably, the firm states it launched deliberately during the 2023 "biotech cold winter," positioning itself as patient, conviction-driven capital willing to back companies when the broader market was risk-off.
Sector Focus
YK Bioventures invests exclusively in biotechnology and life sciences, with a clear preference for platform companies addressing previously intractable biology. Portfolio evidence spans several modalities: RNA interference and tissue-targeted siRNA (Moonwalk Biosciences), regenerative biomaterials and tissue scaffolds (Tempo Therapeutics), synthetic-biology-enabled small molecule drug discovery against "undruggable" targets (Think Bioscience), molecular glue degrader discovery (Triana Biomedicines), immuno-oncology antibodies and NK-cell engagement (Normunity), rare bone and connective-tissue disorder antibodies (āshibio), computational/physics-based small molecule discovery (PsiThera), oligonucleotide medicines delivered to the kidney (Judo Bio), oncolytic gene therapy delivery (Vivere Oncotherapies), regenerative cell therapy for neurological disease (Neurona Therapeutics), regenerative hair-loss treatments (Pelage Pharmaceuticals), and small-molecule pharmacological chaperones for protein misfolding disease (Protego Bio). The through-line is deep-science, platform-driven therapeutics rather than services or digital health.
Stage Focus
Publicly documented rounds show YK Bioventures participating from Series A through Series B, typically alongside a syndicate of specialist life-science and multi-stage technology investors rather than as a solo lead at every stage. The firm both co-leads (Moonwalk Biosciences' $70M Series B, co-led with Alpha Wave) and follows as a syndicate participant (Think Bioscience's $55M Series A; Tempo Therapeutics' $14.5M financing led by Galaxy Sirius Partners). This pattern suggests a flexible lead/follow posture calibrated to conviction and relationship rather than a fixed stage mandate.
Check Size
No specific check-size range is publicly disclosed. Observed round sizes the firm has participated in range from roughly $14.5M to $70M in total round size, but YK Bioventures' individual allocation within these syndicates is not disclosed in any source reviewed.
Lead Tendency
Mixed: the firm has co-led at least one Series B (Moonwalk Biosciences) and participated as a syndicate member (not leading) in at least two other rounds (Tempo Therapeutics, Think Bioscience).
Recent Activity
YK Bioventures has been active through 2026: it co-led Moonwalk Biosciences' oversubscribed $70M Series B (announced September 8, 2026, alongside Alpha Wave, with Eli Lilly, Gaorong Ventures, ARCH Venture Partners, Khosla Ventures and Future Ventures) to advance an adipose-targeted RNAi obesity therapeutic. It also participated in Tempo Therapeutics' oversubscribed $14.5M financing (announced September 2026, led by Galaxy Sirius Partners, alongside Johnson & Johnson Innovation/JJDC, Gideon Strategic Partners and Mesa Verde Venture Partners) to advance the company's MAP regenerative biomaterial toward FDA clearance. Earlier in 2026, it participated in Think Bioscience's oversubscribed $55M Series A (announced January 20, 2026, led by Regeneron Ventures, Innovation Endeavors and Janus Henderson Investors) for the company's small-molecule Noonan syndrome program. In September 2024, an SEC filing indicated the firm was raising a dedicated ~$100M fund, per Endpoints News reporting.
Portfolio Highlights
Notable named portfolio companies include Moonwalk Biosciences, Tempo Therapeutics, Think Bioscience, Triana Biomedicines, Neurona Therapeutics, Pelage Pharmaceuticals, Shenandoah Therapeutics, Normunity, āshibio, PsiThera, Protego Bio, Judo Bio and Vivere Oncotherapies. Several of these companies have gone on to raise large follow-on rounds from top-tier life science investors (ARCH Venture Partners, Regeneron Ventures, Khosla Ventures, Eli Lilly, Alpha Wave), suggesting strong syndicate quality and follow-on validation of YK Bioventures' early picks.
Team
- Gary Yeung — Co-Founder & Managing Partner. Public LinkedIn bio describes bridging breakthrough science and commercial success across three decades in the biotech industry.
- Mitch Kossar — Co-Founder & Chief Investment Officer, based in Burlingame, CA.
The firm is small (LinkedIn lists roughly 2-10 employees / 6 total profiles), consistent with a founder-led, high-conviction investing model rather than a large multi-partner platform.
Decision Process
Not publicly documented in detail, but the two-co-founder structure (Managing Partner + Chief Investment Officer) suggests a partnership-style decision process rather than a solo-GP or large investment-committee model.
Founder Preferences
The firm's public messaging emphasizes backing "scientists and entrepreneurs" translating breakthrough academic or clinical research into companies, and explicitly frames itself as a partner for founders during difficult financing environments ("we were there for companies when the industry needed conviction-driven partners most").
Geographic Focus
Headquartered in Burlingame, California (San Francisco Bay Area). Portfolio companies span the broader US biotech hubs: San Diego (Tempo Therapeutics, Protego Bio), Boston/Cambridge (Judo Bio, Normunity), Boulder, CO (Think Bioscience), and the SF Bay Area (Moonwalk Biosciences, āshibio, Vivere Oncotherapies), indicating a US-wide, hub-agnostic biotech mandate rather than a Bay-Area-only focus.
Co-Investment Network
YK Bioventures publicly lists an extensive co-investment network spanning life-science specialists (TCG, GV, venBio, Atlas, ARCH, Forbion, RA Capital, Samsara, Population Health, Omega Fund, Vida, Droia, Ascenta, MPM), multi-stage technology investors (Lightspeed, Canaan, Khosla, Bessemer, Alpha Wave, Future Ventures, Digitalis, Innovation Endeavors, Viking), specialist/strategic funds (Alexandria, Finchley, Euclidean, Surveyor, Enavate, Cormorant, Soleus Capital, Fidelity, Schroders), and corporate venture arms (JJDC/Johnson & Johnson Innovation, Regeneron Ventures, Pfizer Ventures, Novartis Venture Fund, UCB Ventures).