Investor · Ann Arbor, MI

William U. Martin

Open William in the network graph →

Filings

29

SEC Form D

Connections

188

co-filers

Capital

$569.7M

across filings

Active

Oct 2023

to Dec 2025

Most-connected co-filers (188)

Michael S. Martin · Ann Arbor, MI10 shared Jan R. Garfinkle · Ann Arbor, MI6 shared Jeffrey Williams · Draper, UT6 shared Charles E. Crone, Jr · Ann Arbor, MI5 shared Patti H. Judson · Ann Arbor, MI5 shared Ernest G. Perich · Ann Arbor, MI5 shared Cynthia J. Livesay · Ann Arbor, MI5 shared Timothy G. Marshall · Ann Arbor, MI5 shared Cynthia H. Wilbanks · Ann Arbor, MI5 shared Mark J. Slade · Ann Arbor, MI5 shared Barbara E. Whitman · New York, NY4 shared Andrew Elder · St. Peter Port, Y74 shared Chris C. Ellyatt · St. Peter Port, Y74 shared Yang Yiyong · St. Peter Port, Y74 shared Kevin D. Eng · Short Hills, NJ4 shared Brett D. Fromson · New York, NY4 shared A. P. Davis · Wheaton, IL4 shared Adam Carte · Reno, NV4 shared Vincent J. Dugan · New York, NY4 shared Mark Huntley · St. Peter Port, Y74 shared Catherine Vlasto · St. Peter Port, Y74 shared Arindam Bhattacharjee · St. Peter Port, Y74 shared Peter C. Hames · St. Peter Port, Y74 shared Stephen Birkett · St. Peter Port, Y74 shared

Recent filings (29)

Auron Therapeutics, Inc.Dec 2025 · 7 co-filers$42.3M QuadCP Fund II, LPNov 2025 · 3 co-filers Auron Therapeutics, Inc.Dec 2024 · 7 co-filers$41.8M CubeWorks, Inc.Dec 2024 · 5 co-filers$14.4M Augment Ventures Fund IV, L.P.Dec 2024 · 3 co-filers$75.0M Ecovia Renewables Inc.Dec 2024 · 3 co-filers$4.0M PEPTINOVO BIOPHARMA INC.Dec 2024 · 5 co-filers$10.0M SWC AH, LLCDec 2024 · 6 co-filers Ambient Biosciences, Inc.Dec 2024 · 7 co-filers$5.0M Strata Oncology, Inc.Nov 2024 · 8 co-filers$10.0M Firefly Aerospace Inc.Nov 2024 · 14 co-filers QuadCP Fund II, LPNov 2024 · 4 co-filers QuadCP Fund II, LPNov 2024 · 4 co-filers UNIVERSITY BANCORP INC /DE/Oct 2024 · 6 co-filers$15.0M BGW Ventures IV, LPOct 2024 · 3 co-filers$40.0M Speyside Equity Fund II LPOct 2024 · 3 co-filers Handled, Inc.Oct 2024 · 8 co-filers$3.1M BlastPoint, Inc.Oct 2024 · 8 co-filers$3.0M Campfire Interactive, Inc.Oct 2024 · 5 co-filers$32.8M Auron Therapeutics, Inc.Oct 2023 · 9 co-filers$48.2M QuadCP Fund I, LPDec 2021 · 7 co-filers Arbor Bancorp, Inc.Dec 2021 · 33 co-filers$75.0M Arbor Bancorp, Inc.Dec 2021 · 33 co-filers$75.0M Arbor Bancorp, Inc.Nov 2021 · 42 co-filers$40.1M Genesis Emerging Markets, L .P.Mar 2019 · 31 co-filers

Derived from public SEC Form D (Reg D) filings; entities resolved probabilistically. See William in the interactive graph →