His calls for change have put the country's biggest conglomerates on the defensive, triggered a wave of homegrown activism and turned shareholder returns into a national talking point. That explains why the loss suffered Friday by Mr. Singer's Elliott Management in its proxy battle over Hyundai Motor Co. is unlikely to derail the nascent shift toward more accountability at the business groups that dominate Asia's fourth-largest economy. As more investors mimic Mr. Singer's activist approach, the nation's family-run conglomerates, locally known as chaebol, are increasingly engaging with minority shareholders and acceding to some of their demands.