OUR TEAM

BARNABY WIENER
Founder & Trustee
Barnaby spent thirty years in the investment industry before stepping away in 2024. Treebeard is now his primary occupation. His passion is to find and back talented, purpose-driven entrepreneurs with a vision to change lives for the better. When not doing that he is likely to be found walking (and talking to) his dog or pottering around in boats.
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CASSANDRA WIENER
Founder & Trustee
Cassandra is a lawyer, initially training at Simmons & Simmons before leaving the city to pursue a career in academia. She is now an Associate Professor in Criminal Law at City, University of London, and has recently returned from secondment to the Home Office funded Operation Bluestone project, which has transformed the police response to rape and serious sexual offences. She is now doing similar work with the CPS. Her research area is the criminal law in the context of domestic abuse, and her new book, When Rape is Routine, is a reframe of how we conceptualise domestic sexual offending in law. Cassandra is passionate about all things Treebeard but her particular interest is in the criminal justice strand of Treebeard’s work.

SHISHIR MALHOTRA
Director
Shish has worked in impact investment for the last 10 years and cares deeply about investing capital purposefully. He joined Treebeard in 2020, and currently supports the team and Trustees to make impact investments across a range of sectors and themes. Alongside this he continues to work with other investors, social business, and charities on a variety of impact-focused projects.
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ELISABETH BARRETT
Trustee
Elisabeth has a deep and broad background working to solve societal problems at scale. She is a technology executive, entrepreneur and investor by background, with heavy focus on getting people and culture right, and using data to really know what is going on and solve root problems. Former Executive at Multiverse.io, CEO of AVADO Digital, COO and Partner at Mustard Seed investments and Director at Coursera, Elisabeth has also led data and technology teams at the highest levels of the British government. In another life she would like to play professional golf and be the drummer in a band.

MIKE MOMPI
Trustee
Mike is a co-founder and Managing Partner at Enza Capital, a multi-stage venture capital firm investing in teams using technology to tackle some of Africa's most pressing challenges. An experienced venture investor and entrepreneur, Mike is a Kauffman Fellow and leads the firm from Nairobi, Kenya. He has worked across four continents and serves as Board Director for several high-growth technology companies spanning North, East, West, and Southern Africa.

ANDREW PURVIS
Trustee
Andrew is passionate about businesses solving societal problems, having purpose, doing good and thereby reducing the reliance on the charitable sector. After starting his career with a multinational in SE Asia where he lived in Hong Kong, Vietnam and Japan, Andrew has been CEO of out and out for profit businesses (real estate business in Japan), business with purpose (Neal's Yard Remedies), a social impact motivated business (helping young people access apprenticeships) and 3 years as CEO of a leading UK youth charity and which he helped merge with the Prince's Trust.

