The carrot likely will be even more important than the stick in driving corporate reporting on environmental, social and governance (ESG) issues in the U.S. going forward. Voluntary disclosure of what companies are doing to measure and manage their sustainability performance has worked so far. Eighty-one percent of S&P 500 companies published a sustainability or corporate responsibility report in 2015, up from just 20 percent in 2011, according to research by the Governance & Accountability Institute. “None of that was driven by regulation,” the institute’s executive vice president Louis Coppola told Bloomberg BNA.