For decades, foreign direct investment (FDI) flows between the US and China were a one-way street: American multinationals invested in labor-intensive manufacturing and consumer-oriented operations in China, but Chinese firms had neither motive nor capacity to invest in the US economy. In the past 5 years this situation has changed profoundly, as Chinese investment in the US took off, and, by most measures, now exceeds flows in the other direction. This sea change suggests opportunity, but also a pressing need for policy leadership to ensure a success story does not turn into a new grievance.