Sovereign development funds (SDFs) and strategic investment funds (SIFs) have become increasingly important investment vehicles for sustainable development. This paper explores how the design and governance of these funds aligns institutional capital with large, long-term investments such as infrastructure, all while yielding high commercial returns for institutional investors. Using the National Investment and Infrastructure Fund (NIIF) of India as a case study, this paper demonstrates how SIFs can crowd-in private capital into strategic assets via collaborative investment models. The paper thus offers a blueprint for how large, long-term institutional capital can be channeled into long-term projects that support economic growth and innovation.