Investor · Framingham, MA

Ernst Schaefer

Open Ernst in the network graph →

Filings

5

SEC Form D

Connections

27

co-filers

Capital

—

across filings

Active

Mar 2009

to Dec 2025

Most-connected co-filers (27)

Peter D. Parker · Framingham, MA3 shared Martin J. Byrne · Grand Cayman, Cayman Islands2 shared Joseph W. Thompson · DALLAS, TX2 shared Kenneth S. Canon · DALLAS, TX2 shared Nimrod J. Hacker · DALLAS, TX2 shared Paul H. Stevenson · Hamilton, Bermuda2 shared Peter M. Kolchinsky · Boston, MA2 shared Susan Hertzberg · Framingham, MA2 shared Thomas Kully · Chicao, IL2 shared Steven Katznelson · Bala Cynwyd, PA2 shared Jennifer Ernst · Fremont, CA2 shared Christina Valauri · Fremont, CA2 shared Michael Handley · Fremont, CA2 shared Sheryle Bolton · Fremont, CA2 shared Lisa Wolf · Fremont, CA2 shared Dean Zikria · Fremont, CA2 shared Michael Snyder · Burlingame, CA2 shared Sandalwood Associates Inc · New York, NJ2 shared Lauren Compere · Boston, MA2 shared Frank B. Yunes · Framingham, MA2 shared Wolfgang Daum · Framingham, MA2 shared Bela Asztalos · Framingham, MA2 shared Chris Riedel · Framingham, MA2 shared Katsuyuki Nakajima · Framingham, MA2 shared

Recent filings (5)

Tivic Health Systems, Inc.Dec 2025 · 17 co-filers$75.0M Tivic Health Systems, Inc.Dec 2025 · 17 co-filers$16.3M Boston Heart Diagnostics CorpOct 2011 · 6 co-filers$6.5M Boston Heart Lab CorpAug 2010 · 16 co-filers$10.0M Boston Heart Lab CorpMar 2009 · 13 co-filers$1.0M

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