Antitrust law is at the center of today’s public debate. It has even emerged as a rare unifying force, with bipartisan promises to combat the concentration of economic power, starting with breaking up Big Tech. Meanwhile, the business and investment community is grappling with mounting systematic risks arising from the pandemic, climate change, income inequality, and racial injustice. Unexpectedly, the largest asset managers in the world find themselves on the front lines of these battles. Due to the rise of index investing, these “universal owners” manage portfolios that are so large and diversified, their holdings mirror the entire economy. Their diversification protects them against idiosyncratic risk, but greatly exposes them to these systematic risks.The universal owners are keenly aware of their exposure to these systematic risks. They are turning to their portfolio companies and increasing demands on directors and managers to “serve a social purpose” and reduce their negative externalities. Public-regarding pronouncements from CEOs of Wall Street’s biggest firms ring hollow to many shareholder primacy loyalists. But the skeptics are missing the economic logic underlying this paradigm shift—diversified shareholders do not want companies to externalize their negative impacts onto the rest of the investors’ portfolios. Many companies are rising to the challenge and making bold commitments. However, many are recognizing that, to satisfy pervasive social and environmental challenges, they must collaborate with their competitors. This Article reveals that current antitrust law is a barrier to this collaboration and offers a policy proposal for aligning antitrust law with the demands upon the prosocial corporation. The COVID-19 pandemic has taught us that we are all interconnected. Climate change will continue to deepen that understanding. The problems we face are difficult, but they are not insurmountable. To solve them, we must value collaboration at least as much as we value competition.