Meet our trustees
Optima’s trustees bring richly varied experience and expertise across finance, law, education, philanthropy, corporate social responsibility, and social impact. They share a deep passion for education and the change it can influence across society.
Sarah chairs Optima’s Board with her significant expertise in philanthropy and corporate social investment. She practised law in London before serving as COO at Tshikululu Social Investments from 2007 to 2012. Her legal background has helped her develop meaningful approaches to strong governance and equipped her with the ability to think clearly on roles and responsibilities. Sarah chairs the Grindrod Family Centenary Trust and serves on a number of foundation boards. She is committed to the idea of fairness and believes that everyone should be educated and live with dignity.
Sarah Rennie (Chair)
Brian joined Optima as a trustee in 2022, and as chair of its Finance, Investment and Risk Committee. He is a former chair of RSM South Africa, where he was the CEO until 2020, and a former member and chair of RSM International’s Board. His career spans five decades of advising family businesses and corporate restructuring, and he continues to consult in this field. Brian is a chartered accountant and has publicly presented on a range of topics at national and international events. He’s deeply involved in charitable trusts that support education and the arts.
Brian Eaton
Michael joined Optima in 2021 after 44 years in the accounting profession. As a former KPMG partner, he specialised in manufacturing and wholesale audits. His experience as an auditor has equipped him with the ability to engage with people at all levels. He’s passionate about education, having worked extensively with NGOs focused on mathematics, science and technology, and has served on various professional bodies involved in training and developing young accountants. Michael is on Optima’s Finance, Investment and Risk Committee.
Michael Evans
Phumla chairs Optima’s Programmes Committee. She has extensive experience in education and development through her roles at the Standard Bank Tutuwa Community Foundation and Tshikululu Social Investments. Now at Absa Corporate Citizenship, she serves on the boards of the rural education access programme and the Equality Collective. Phumla holds a master’s in development and management with a focus on corporate social responsibility. This grounds her deeply in her commitment for social impact, ethical leadership, and sustainable development.
Phumla Hobe-Yabo
Margie has been one of Optima’s trustees since 2006, playing an instrumental role in its establishment. She is also the chair of Optima’s Strategy Committee. Margie led the Anglo American and De Beers Chairman’s Fund, and founded Tshikululu Social Investments where she was CEO from 1998 until 2008. She is a social impact leader in South Africa with more than three decades of experience. Based in Makhanda, Margie chairs the Rhodes University Vice Chancellor’s Education Committee and serves as GADRA Education’s treasurer. She consults on development projects and actively engages in community activism.
Margie Keeton
Siya joined Optima as a trustee in 2025 and is a Finance, Investment, and Risk Committee member. He is also a Partner at Vuna Partners, a private equity fund manager he co-founded in 2020. Siya is a chartered accountant and has served on various company boards and not-for-profit organisations, namely the Southern African Venture Capital and Private Equity Association (SAVCA). Siya’s passion for education emanates from his parents, who were school inspectors and lectured at various teachers’ colleges in KwaZulu-Natal.
Siya Nhlumayo
With expertise grounded in law and investment banking compliance, Philippa joined Optima in 2007. She holds legal qualifications from Wits and UCT and is a former partner at legal firm Webber Wentzel, and has worked at institutions such as the Johannesburg Stock Exchange and Deutsche Bank SA. Philippa finds deep interest and excitement in the possibility of creating systemic change in early stage numeracy learning. She also actively supports young people through scholarships and philanthropic initiatives in her personal capacity. Optima’s professional and academic approach to education is what draws her to serving as a trustee.
Philippa Sauvenier
Meet our team
Our small, complementary and dynamic team is driven by our purpose to give every schoolchild in South Africa a strong foundation. With diverse backgrounds in programme management, psychology, social investment analysis, and research, we bring both strategic insight and hands-on experience to deliver evidence-based solutions that drive sustainable impact at scale.
With twenty years of experience in South African philanthropy, Sarah leads Optima, driven by a deep commitment to fairness and equity. She views education as a fundamental enabler and equaliser. Sarah is passionate about philanthropy’s potential to support scalable programmes that benefit all children, advocating for collaborative, practical solutions. She understands that achieving sustainable, large-scale impact requires strong partnerships, particularly with government. Sarah believes that bringing in diverse perspectives is key to solving complex challenges in the education sector. She loves learning and is almost always enrolled on a course. To recharge, Sarah enjoys running while listening to podcasts.
Sarah Cairns
Head of trust
Kabelo manages Optima’s programmes. She has nine years’ experience in the education sector, working with multiple stakeholders to ensure Optima’s programmes meet their objectives and align with the organisation’s vision. She believes classrooms and teachers can change a child’s outlook on life. She saw this when mentoring girls at the outset of her career. Her practical, results-focused approach makes her a great troubleshooter, and her psychology training has helped her build solid relationships with implementing partners. Kabelo thinks the way to improve the education sector is for like-minded people to come together. Kabelo loves spending time with family and friends, attending concerts and outdoor events.
Kabelo Mosate-Dambuza
Programme management
As a project manager with a great understanding of administrative systems, Tsepo engages directly with schools, working with interns to make sure they get the support they need to qualify. From his previous role helping rural students get into university, he understands challenges in the sector, from limited access to facilities to the financial constraints of intern teachers in urban settings. A strong believer in not letting your background determine where you want to go, he loves seeing young people reach their potential. He’s an optimist by nature who brings fresh perspectives to his work through his sense of humour. Tsepo throws himself wholeheartedly into everything he does.
Tsepo Senoamali
Project management
Khebi keeps Optima’s operations running smoothly. She’s structured, reliable and organised, so it’s hardly surprising that she’s studying towards a degree in public administration. But her ability to get things done while keeping the team connected and effective is far from the only reason she’s indispensable. She’s formed genuine connections with everyone in the team to make each member feel individually valued and supported. Colleagues note how she patiently anticipates needs, makes sure nothing falls through any cracks, covers everyone’s backs and ensures every project stays on track. Her big heart, collaborative mindset and unwavering consistency make her the steady presence everyone at Optima counts on.
Khebi Sibanyoni
Administration
Aarti has an insatiable curiosity and finds almost everything interesting. Give her a topic, and she will dive deep into it, researching until she's uncovered nearly every angle. This curiosity motivates her to connect seemingly unrelated ideas in creative ways. She thrives in collaborative environments, where diverse perspectives and contrasting viewpoints help shape the understanding of a problem and lead to well-defined solutions. Aarti enjoys the process of zooming in on the finer details while also zooming out to ensure the broader context is always in focus. She also values the use of evidence-driven narratives to shift mindsets and drive meaningful change. The Optima team finds her enthusiasm for stationery amusing.
Aarti Shah
Strategy and research
Administrative management and governance
Tshikululu Social Investments provides fund administration support to Optima, which includes monitoring and evaluation, financial oversight, compliance, and governance.