Horizon Holdings, LLC

Horizon’s two co-founders and principals, Phil Estes and Jim Shorin, have significant experience in most important corporate functions including capital formation, business strategy, executive recruiting, management compensation plan formulation, finance and control, law, operations and sales and marketing.  Although our formal educations are aged and might be mistakenly considered high-brow by some, our approach is decidedly low key and is tempered by real world experience and humility.  

James M. Shorin

James M. Shorin

Managing Member

Jim serves as a Board Member of each of Horizon’s investments.  Jim is a supporter of youth sports in his community and is an avid photographer who regularly shoots various sporting events for Stanford University.  Jim holds a JD from Stanford Law School, an MBA from the University of Chicago and a BA from Duke University.  He is a member of the California State Bar and has passed the Certified Public Accountant exam.  Prior to founding Horizon, Jim was a consultant with Bain & Company, a leading management consulting firm.

Find out more about Jim

Phillip S. Estes

Phillip S. Estes

Managing Member 

In addition to serving as a Board Member of each of Horizon’s investments, Phil is an active community leader and is particularly engaged in philanthropy and non-profit work in the human service and education fields.  He serves on a number of non-profit boards and is an active volunteer and advisor with a number of organizations, including Larkin Street Youth Services and REDF.  In 2011, he received the Jefferson Award for Public Service.  He holds an MBA from Harvard Business School, completed coursework for an MS in Petroleum Geology from Stanford University and holds a BS in Geology from the University of Oklahoma.  Prior to founding Horizon, Phil was an investment banker at Drexel Burnham Lambert.  In his spare time, Phil is a drummer for an aspiring rock band.    

Find out more about Phil

Colleen Planting

Colleen Planting

Executive Assistant and Office Manager

Colleen joined Horizon Holdings in 2015 as Executive Assistant and Office Manager. She manages the firm's day to day administration, including travel and logistics, office operations and banking, and certain corporate matters for Horizon's portfolio companies. Before joining the company, Colleen was EA and Office Manager at d.light design, a for profit social enterprise with offices in Kenya, Delhi, Shenzhen and San Francisco. Prior to d.light, she held various EA/Office Manager positions in the financial services sector, primarily for high level executives in the financial district of San Francisco, including Gryphon Investors and Bessemer Trust. Her hobbies include golf, dancing, hiking, cooking and entertaining family and friends.