HORIZON - Key Persons


Colleen Planting

Job Titles:
  • Executive Assistant
  • Office Manager
  • Executive Assistant & Office Manage R
  • Holdings in 2015 As 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.

James M. Shorin

Job Titles:
  • Managing Member
  • Board Member of Each
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.

Phillip S. Estes

Job Titles:
  • Community Leader
  • 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.