The DOJ withdrew a decades-old approval letter for ISS, signaling that the duopoly controlling over 90% of proxy advisory services may face serious regulatory headwinds. The firm now provides advisory services on executive compensation and governance to the very corporations whose shareholders it also advises. President Trump signed an executive order in December 2025 instructing multiple federal agencies to review antitrust investigations concerning proxy advisors. The Department of Labor added another layer in April 2026, issuing new guidance examining whether proxy advisory firms could be classified as ERISA fiduciaries. What this means for investors and marketsThe withdrawal of the Business Review Letter doesn’t immediately change anything operationally for ISS.