This dissertation examines how climate and sustainability risks affect firms, investors, and philanthropic capital, and how institutional mechanisms shape their responses. As climate-related disasters become more frequent and environmental risks become more financially relevant, understanding the institutions that influence adaptation and response is increasingly important. Across three chapters, I study how insurance, corporate disclosure, and charitable intermediaries affect financial and economic responses to natural disasters and emerging sustainability risks. Chapter 1 examines how firms recover after floods and provides novel causal evidence that mandated flood insurance materially shapes business recovery. Using establishment-level data that link remote-sensing inundation to FEMA flood maps, I combine a triple-difference design around Hurricane Sandy with a spatial regression discontinuity at floodplain borders and show that flooded establishments just inside floodplains recover more in employment and sales than otherwise similar establishments just outside, consistent with an insurance-liquidity channel that supports rebuilding and reallocation. Chapter 2, co-authored with Miao Liu, Yao Lu, and David Ng, examines how firms disclose biodiversity risk exposure in 10-K filings and how investors respond. It shows that firms are more likely to provide direct disclosures when information demand is higher, while investors respond more strongly to indirect disclosures. Chapter 3, co-authored with Yipiao Cai, David Ng, and Jie Ying, examines how donor-advised funds respond to natural disasters. Using Form 990 e-filing data, it shows that although contributions rise following disasters, grantmaking does not increase proportionately, with responses occurring mainly through reallocations toward more visible recipients.