Onnie Mayshak

Partner – Portfolio Management and Private Investments

Onnie is a Partner and Portfolio Manager at Proficio Capital Partners. In his role, Onnie manages the investment portfolios for Proficio families, providing them guidance on complex financial issues and opportunities. Onnie also serves on the firm’s investment committee where he splits his time on both public and private investment solutions leveraging his experience across multiple asset classes to assist in the sourcing and diligence of new investment ideas.


Prior to joining Proficio, Onnie was a VP of Investor Relations/Business Development at Landmark Partners, where he guided the firms capital acquisition strategy and represented Landmark’s private equity, real estate and infrastructure investment funds to both existing and prospective investors. Onnie spent the first 10 years of his career at Susquehanna International Group, where served in both market-making and derivatives strategy roles. Thereafter at Ned Davis Research, he managed the distribution team for the northeast, and provided investment advisory and asset allocation recommendations to professional investors including institutional clients and high net worth individuals. Onnie has extensive expertise in product development, and both public and private markets.


Onnie holds a Bachelors of Science in Environmental Science and Public Policy from Harvard University, where he played on the mens varsity basketball team.

Outside the Office

Onnie resides in Needham with his wife and two children. He is active in the community and serves on the Board of Directors at the Boys and Girls Club of Boston, and the investment committee for the Frederick E Weber foundation. He also served as a “big” for Big Brothers/Big Sisters of Massachusetts Bay. Onnie grew up in the Toronto area and is an avid Toronto Raptors fan.