The highlights of the illuminem Leader's Cohort in 2026
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Most of what Chief Sustainability Officers know, they don’t say publicly. The true insights – what it actually takes to get a CFO to put a number on reputational risk, how you keep a circularity programme alive when the board calls it cannibalisation, what to do with a nature mandate and no budget to execute it – stays in private conversations behind closed doors.
illuminem's Sustainability Leaders Cohort brings those conversations into a structured setting. Once a month, a small group of CSOs and senior sustainability executives meets in a closed session, chaired by Gregg Meyer, CSO of Steve Madden. illuminem provides the data infrastructure and convening capacity; members bring the operational reality.
The three sessions documented below cover the ground that has dominated the function in early 2026: making the internal financial case for sustainability investment, navigating a regulatory environment that has grown simultaneously more demanding and less predictable, and getting to grips with nature and biodiversity as the next frontier CSOs are being asked to own.
The illuminem Sustainability Leaders Cohort is an invite-only membership for Chief Sustainability Officers and senior sustainability executives. Sessions are monthly and limited in size to preserve the quality of conversation, chaired by Gregg Meyer, CSO of Steve Madden, with one keynote expert supporting the discussion.
Members receive access to monthly C-level best practice sessions; illuminem's ESG benchmarking database covering 1M+ data points across 10,000 companies and 250+ KPIs; speaker placements at major sustainability events including COP31, New York Climate Week, London Climate Action Week, and Davos; and monthly 1:1 strategic calls with illuminem's advisory team.
The dominant shift observed by our CSOs was that boards have stopped treating sustainability spend as self-justifying. The ask now is the same as any other capital allocation: show the maths. For most CSOs, that is a skills gap as much as a communications problem, because the return on even the hardest initiatives is a risk avoided rather than a revenue line.
The most useful reframe that emerged was to stop positioning sustainability as a values argument and start positioning it as risk intelligence. The framing that landed with one CEO – "be the firefighter, let us help you think about building the kitchen up again" – worked because it shifted the CSO from moral advocate to strategic partner.
On the subject of deadstock, our CSOs discussed the internal resistance to circularity over fears of cannibalisation. What incited action in one case was reframing deadstock as reputational exposure: "we are in trouble if the media picks up on this." In that case, the deadstock was donated to design students, leading to overall greater PR value.
On sustainable products, an A/B study shared in the session found 10% higher purchase intent for a sustainable variant at the same price point. The moment prices diverge, the advantage disappears, but at parity the preference is measurable and consistent.
The session's closing line, from a fashion CSO: "You can't convince everyone and you shouldn't." Knowing which stakeholders to deprioritise is itself a strategic decision.
February discussion was pervaded by the themes of regulation uncertainty and fragmentation. CSOs expressed how delays, rollbacks and uneven timelines from CSRD, ESPR, UK SRS, California rules have created planning ambiguity and risk of duplicated work across regions. The result, as one CSO put it, is duplicated work across regions and genuine uncertainty about where to invest compliance resources. One practical response that gained traction: pick the strictest applicable standard (in several cases, CSRD) and use it as a single global baseline. It reduces governance overhead and makes supplier requests consistent.
The Cohort also discussed the how reporting is consuming resources that used to go into actual decarbonisation work. One CSO noted a peer organisation with 200 people working on reporting rather than on the mission. The session's practical answer was to treat regulatory delays as a preparation window and use the time to get systems ready so implementation is cheaper when enforcement arrives.
On the topic of opening doors in getting CEOs to embrace CSR, two reframes worked for some of our CSOs: position sustainability as modernisation and operational resilience rather than ideology; and treat Digital Product Passports as a commerce and consumer engagement opportunity, which brought marketing and e-commerce teams into the funding conversation.
Nature and biodiversity have arrived on the CSO agenda faster than most organisations have been able to build the internal capacity to act on them. The March session was largely about closing that gap practically.
The starting point most found useful: materiality mapping – identifying where in operations and supply chain the actual dependencies and exposures sit, using geospatial tools to prioritise the highest-risk sites. Staged targets (near-term site actions, medium-term supply chain interventions, longer-term nature-positive outcomes) give the work a structure that boards can track.
On metrics, illuminem's Nature100 study proved a valuable point of reference. Drawing on 100,000 business nature datapoints, it suggests eight comparable KPIs that can function as corporate benchmarks: land use change, greenhouse gas emissions, water consumption, waste generation, and four pollutant emissions categories, each quantified by their potential contribution to global species loss.
The note of caution that closed the session: biodiversity credits are attracting significant attention but should be treated as part of a broader strategy, not a substitute for direct action. The organisations that have moved furthest are those that secured board understanding early, defined internal ownership clearly, and allocated budget incrementally rather than waiting for a comprehensive mandate.
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