Open Field Capital seeks to capture alpha from the market dislocations that result when rapid technological innovation occurs. The greatest investment opportunity exists where the emergence of a new technology creates an entirely new market, an open field.

Open Field’s opportunity to invest in technological innovation broadens as technology proliferates more of our economy. Underlying the rapid disruption that ensues are powerful, long term and evolving trends in technology, such as mobile computing, virtual / cloud computing and artificial intelligence.

These ‘megatrends’ are both self-reinforcing and convergent. Combined, they provide the framework of Open Field’s investment strategy as we search for public and private companies that can sustain rapid growth and create enduring franchise value.


Open Field Capital LLC was established in August of 2003 with the exclusive focus of managing portfolios in emerging technology equities that are both public and private. It is Open Field Capital’s core philosophy that disruptive technologies are the best driver of sustained equity out performance.

The founding principals of Open Field Capital have worked together for over 17 years and have a substantial depth and breadth of experience in the financial markets. Throughout that time, the principals have worked in emerging technology markets and have developed both an investment philosophy and methodology tailored to the sector's unique characteristics.


Marc Weiss

Chief Investment Officer

MARC WEISS is the Open Field Chief Investment Officer and a member of its four person Investment Committee. Mr. Weiss joined Open Field full time in 2005. Mr. Weiss joined Amerindo Investment Advisors Inc. in 1994 and became its Director of Research in 2002 as well as serving as one of five members of its Investment Committee. Prior to joining Amerindo Mr. Weiss was a Senior Associate Engineer with IBM between 1989 and 1992 where he authored 2 patents (5670018 and 6258497). Mr. Weiss was a founding partner of Open Field Capital LLC and Open Field Investors LP. Mr. Weiss holds a B.S. in Electrical Engineering from Rensselaer Polytechnic Institute, an M.Eng. in Electrical Engineering from Cornell University, and an M.B.A. from Columbia University.

James Stableford

Director of Portfolios
Chief Compliance Officer

JAMES P.F. STABLEFORD is the Open Field Director of Portfolios, Chief Compliance Officer, and a member of its four person Investment Committee. He began his career in 1985 with Prudential Bache Securities in London, where he served for a year as a broker's assistant until moving to Cigna International Investment Advisors, where he served in operations and as a portfolio assistant from 1986 through October 1987. From 1989 until joining Open Field fulltime in 2003, he served in operations and portfolio management for Amerindo Investment Advisors UK Ltd and was one of five members of Amerindo's Investment Committee. Mr. Stableford was a founder of Open Field Capital LLC and Open Field Investors LP. Mr. Stableford holds a BSc in Economics from Brunel University in Middlesex.

Robert Griffin


ROBERT M. GRIFFIN is a member of Open Field’s Investment Committee. Mr. Griffin holds a BA Hons 1st in Finance from the European Business School of London. He began his career in 1996 with J P Morgan Securities in London as a graduate trainee in Mergers and Acquisitions. In September 1997 Mr. Griffin took up a role as Portfolio Analyst at Amerindo Investment Advisors UK Ltd from which he progressed to Assistant Portfolio Manager until October 2003, at which time he left to dedicate his full time to help establish the Open Field companies, the first of which began operating in January 2004. Mr. Griffin is a founding partner of Open Field Capital LLC.

Michael Sandifer


MICHAEL J. SANDIFER is a member of Open Field's four person Investment Committee. He began his financial career with Brown Brothers Harriman in New York in 1970 where he became an Investment Officer in the International Department. From 1973 to 1976, he served as a Principal of Baker Weeks & Co., one of the original institutional investment research firms on Wall Street. In 1976, that firm was acquired by Reynolds Securities, where Mr. Sandifer became Vice President in charge of the firm's nine office international network. In 1977, Reynolds was merged with Dean Witter, and Mr. Sandifer served as an International Vice President. From 1978 to 1982, he held various positions in research, sales and management at Donaldson Lufkin and Jenrette in New York and became Regional Vice President in charge of the firm's businesses in the twelve western states out of its San Francisco office. After a brief period at Montgomery Securities in San Francisco in 1982, he became a Partner of the investment banking and venture capital firm of Woodman Kirkpatrick & Gilbreath which specialized in medical and electronic high technology. In 1984 that firm was acquired by Hambrecht & Quist, one of the premier firms in the same area of expertise. Mr. Sandifer was a Principal at Hambrecht & Quist from 1984 to 1990, where he initially served from its San Francisco office before moving to London to manage the firm's European sales effort. Subsequently he moved to New York where in 1990, he became associated with Amerindo Investment Advisors Inc., first as an employee and then as a consultant, where he served as one of five members of Amerindo's Investment Committee. Mr. Sandifer was a founder of Open Field Capital LLC and Open Field Investors LP and joined Open Field full time in 2005. Mr. Sandifer holds the degrees of B.A. in Economics from Occidental College in Los Angeles and a J.D. from the University of California at Los Angeles.

Luis Scull Baptista

Senior Research Analyst

Luis Scull serves as Open Field Senior Research Analyst. He began his career at Amerindo Investment Advisors Inc, where he served as a Research Associate in 2005. In 2006 he joined Open Field where he began as a Junior Research Analyst, progressing to become the Research Analyst and most recently the Senior Research Analyst. Luis is particularly focused on the areas of Cybersecurity, Big Data enterprise SaaS and South American Internet companies. Luis holds a bachelor’s degree in Political Science with a minor in Economics and Latin American Studies from Pace University. He is a Native of South America and is fluent in Spanish.

Yixin Zeng

Junior Research Analyst

Yixin Zeng is a Junior Analyst in Open Field Capital where he has worked since 2011. Yixin focuses on the vast Chinese Internet sector. He also holds a bachelor’s degree in Computer Science from Shanghai Jiao Tong University as well as a M.S. degree in Financial Engineering from New York University. Yixin is a CFA level 3 candidate, a native of Shanghai and is fluent in Mandarin. 



Since 2005, Open Field Capital has managed long only portfolios of high growth publicly traded stocks in the technology sector.

Open Field's long only clients include institutional investors, family offices and high net worth individuals. Open Field's success comes from combining the mantra of buy and hold with a proactive management of cash weightings. This strategy has enabled Open Field to exploit the buying opportunities provided by the stock price volatility of fast growing technology companies.

We believe the technology sector is the most important generator of wealth for the US economy, as evidenced by the success of companies such as these: