Sigma Lithium Recognized as Sustainability and Cleantech Pioneer at UN-Climate Week in NY Featuring Lithium Oxide Industrialization; Continues to Operate Following Brazil's Democratic Rule of Law

Toronto, Ontario--(Newsfile Corp. - September 28, 2026) - Sigma Lithium Corporation (NASDAQ: SGML) (ASX: SAU) (TSXV: SGML) (BVMF: S2GM34) ("Sigma Lithium" or the "Company"), the largest producer of industrial-mineral lithium oxide concentrate in the Americas¹ and dedicated to supplying global producers of batteries for energy security with sustainable and traceable lithium materials, announces that: * Sigma Lithium Co-Chair, CEO and Vice Presidents ("Senior Leaders") joined UN-Energy members in several forums throughout United Nations General Assembly High-Level Week, contributing to discussions and initiatives across the energy transition, industrial transformation, investments, energy access and resilience.

* Sigma Lithium was featured in several forums at UN-Climate Week in NY for its pioneer investment to develop clean technologies to industrialize lithium oxides at low cost, producing at scale the Quintuple Zero Lithium:* Zero Mud Tailing Dams * Zero Use of Potable Drinking Water * Zero Use of Non-Renewable Power * Zero Use of Highly Toxic Chemicals