Energy Transition/ Executive Moves/ Investors

Nuveen Appoints Costas Papamantellos as Head of Energy Transition Investments

Mark Segal October 8, 2025

Global investment manager Nuveen announced the appointment of former RWE senior executive Costas Papamantellos as Head of Energy Transition Investments, as part of the firm’s Clean Energy Infrastructure team.

The new appointment follows the announced launch by Nuveen earlier this month of its new dedicated Global Infrastructure Investment Platform, combining several of its infrastructure-focused teams, including its Clean Energy Infrastructure, Diversified Infrastructure, and Digital Infrastructure equity teams, as well as its private credit-focused Nuveen Energy Infrastructure Credit, and its sustainable commercial real estate financing solutions business Nuveen Green Capital.

Papamantellos joins Nuveen after more than 17 years at German power producer RWE, most recently serving as Managing Director & Head of Energy Transition Investments, as well as Chairman & CEO at RWE Renewables Hellas, a joint venture developing 1.5 GW solar pv projects.

Based in London, Papamantellos will report to Joost Bergsma, Global Head of Clean Energy at Nuveen.

Mark founded ESG Today following a 20 year career in investment management and research. Prior to founding ESG Today, Mark worked at Delaney Capital Management (DCM) in Toronto, Canada, most recently as the firm’s head of U.S. equities. While at DCM, Mark was part of the firm’s ESG team, responsible for evaluating and tracking the sustainability factors impacting portfolio companies, and assessing the suitability of companies for portfolio inclusion. Mark also spent several years in the sell-side research industry, covering the technology and services sectors. Mark holds an MBA from Columbia University in New York, a BBA from the Schulich School of Business at York University in Toronto, and is a CFA charterholder.