Gregory Kiernan

Greg Kiernan is the President, CEO, and a co-founding partner of Sonostar Ventures LLC, an investment, private equity, and venture capital firm he established with his longtime partner David Moore in April 1997. Kiernan and Moore have been business partners for more than 50 years, dating back to their undergraduate days at Amherst College. Their partnership was formalized after an early success restructuring a troubled publicly traded home-improvement company beginning in 1995, which generated the capital that seeded their venture activities. From 1997 to 2005, the firm's portfolio reportedly produced more than 460% in cumulative realized gains.

From 2005 to 2016, Kiernan founded and served as Managing Partner of Sonostar Capital Partners, a $20+ million fund pooling capital from roughly fifteen investors to pursue early-stage entrepreneurial ventures. He was the fund's largest investor, contributing about 25% of its capital, and oversaw all aspects of its investments. The email domain "sonocap.com" and the CB Insights profile "sonostarcapital.com" both refer to this Sonostar Capital Partners vehicle.

Before founding Sonostar, Kiernan spent his career on Wall Street, working at Lehman Brothers and Salomon Brothers before roughly a decade at PaineWebber, where he rose to Senior Managing Director in charge of the firm's institutional Corporate Bond, High Yield, Preferred Stock, and Mortgage-Backed Securities departments. Prior to Wall Street, he practiced law as an attorney at Cravath, Swaine & Moore, admitted to the New York State bar.

Kiernan earned a B.A. from Amherst College (magna cum laude, Phi Beta Kappa) and a J.D. from Harvard Law School. He serves on the boards of several majority-owned portfolio companies and has been active in charitable education initiatives for underserved children. He lives in Chappaqua, New York, with his wife Vera and has five grown children; his son James Kiernan joined Sonostar as a Managing Director in 2022.

• Invests as a principal/angel and through Sonostar's funds across a diversified book: biotech, direct-to-consumer commerce, real estate, hedge funds, digital assets, and specialty credit — emphasizing "strong management teams, clear paths to profitability, and meaningful return potential."
• Concentrates most heavily in life sciences/biotech, where Sonostar takes founder stakes and follows companies across private and public rounds — even buying additional shares in the public market at distressed levels when conviction is high (as it did with Allogene Therapeutics sub-$2 and Global Blood Therapeutics).
• Comfortable at the seed stage (its primary entry point) but will follow winners deep into growth, late-stage, and public equity, blurring the line between angel, VC, and PE.
• Values track record and profitability discipline: highlights portfolio companies by revenue and EBITDA milestones (e.g., "$100M+ revenue run rate," "EBITDA positive") rather than vanity metrics.
• Willing to be opportunistic and event-driven — e.g., establishing a large GBT position in the low $30s in Q4 2018 ahead of an FDA approval catalyst and exiting in the mid-$70s in Q4 2019.