Investor · Boston, MA
William H. Koster
Open William in the network graph →Filings
24
SEC Form D
Connections
180
co-filers
Capital
$46.1M
across filings
Active
Jun 2020
to Dec 2022
Most-connected co-filers (180)
Kerrie H. Brady · Boston, MA14 sharedWilliam S. Steinkrauss · Boston, MA10 sharedRobin H. Steele · Boston, MA10 sharedD. S. Edwards · Boston, MA9 sharedDavid J. Tanzer · Boston, MA8 sharedBarbara Ryan · Sarasota, FL8 sharedPaul Beldin · DENVER, CO8 sharedDavid Edwards · Lexington, MA7 sharedBruce P. Failing · Darien, CT6 sharedBrenton S. Saunders · Boston, MA6 sharedRobert H. Ruffolo · Boston, MA6 sharedRam Ahluwalia · New York, NY6 sharedMatthew Ross · New York, NY5 sharedMark K. Walker · Steamboat Springs, CO4 sharedJamie Jenny · Steamboat Springs, CO4 sharedDana E. Tredway · Steamboat Springs, CO4 sharedLarry Ellgen · Steamboat Springs, CO4 sharedRobert E. Milne · Steamboat Springs, CO4 sharedCharles E. Macarthur · Steamboat Springs, CO4 sharedSuzanne E. Schlicht · Steamboat Springs, CO4 sharedGlenn Wyer · Minneapolis, MN4 sharedScott Cook · Steamboat Springs, CO4 sharedRobert Zulkoski · Minneapolis, MN4 sharedPatrick Barney · Steamboat Springs, CO4 shared
Recent filings (24)
Routt County Bancorporation, Inc.Jul 2025 · 56 co-filers$4.8MRoutt County Bancorporation, Inc.May 2025 · 56 co-filers$4.8MRuralWorks Impact Partners 1, L.P.Sep 2024 · 10 co-filers$49.5MRuralWorks Impact Partners 1, L.P.Aug 2024 · 10 co-filers$150.0MRoutt County Bancorporation, Inc.May 2024 · 50 co-filers$4.3MOcuTerra Therapeutics, Inc.Feb 2024 · 29 co-filers$25.6MOcuTerra Therapeutics, Inc.Feb 2024 · 29 co-filers$25.6MOcuTerra Therapeutics, Inc.Dec 2023 · 29 co-filers$30.0MOcuTerra Therapeutics, Inc.Dec 2023 · 29 co-filers$30.0MRoutt County Bancorporation, Inc.Jul 2023 · 47 co-filers$3.7MRuralWorks Impact Partners 1, L.P.Jun 2023 · 16 co-filers$150.0MPalvella Therapeutics, Inc.Dec 2022 · 23 co-filers$37.7MArgo Blockchain PlcJul 2022 · 17 co-filers$10.0MRuralWorks Impact Partners 1, L.P.Jun 2022 · 16 co-filers$150.0MArgo Blockchain PlcJun 2022 · 17 co-filers$141KOcuTerra Therapeutics, Inc.Aug 2021 · 20 co-filers$50.0MAgile Sports Technologies, Inc. dba HudlMay 2021 · 32 co-filers$182.5MSciFluor Life Sciences, Inc.May 2021 · 20 co-filers$40.0MAgile Sports Technologies, Inc. dba HudlJun 2020 · 31 co-filers$182.5MAgile Sports Technologies, Inc. dba HudlJun 2020 · 32 co-filers$182.5MPalvella Therapeutics, Inc.Jun 2020 · 27 co-filers$45.0MSciFluor Life Sciences, Inc.Sep 2019 · 4 co-filers$1.5MVedantra Pharmaceuticals, Inc.Jun 2018 · 20 co-filers$3.0MVedantra Pharmaceuticals, Inc.May 2016 · 7 co-filers$1.5MMnemosyne Pharmaceuticals IncFeb 2015 · 11 co-filers$13.0M
Derived from public SEC Form D (Reg D) filings; entities resolved probabilistically. See William in the interactive graph →