This article provides the theoretical foundation for the concept of “Underwaterwriting,” which can be understood as various informational and institutional limitations related to environmental exposure and climate change impacts—specifically flooding and sea level rise inundation—shaping firm participation in mortgage markets. Underwaterwriting suggests that the unevenness of scientific knowledge and local soft information, as well as the institutional barriers for the utilization of that information, could result in determinations of risk that may not accurately reflect long-term asset performance or credit loss. These informational asymmetries may result in assignments of risk that reflect a degree of arbitrariness or inaccuracy that may operate to strand assets and shed or increase market share in ways that are inefficient and may otherwise lead to negative public externalities. Consistent with this theory, this article provides evidence that concentrated local lenders are transferring risk in high-risk coastal geographies in the Southeast Atlantic and Gulf Coasts (U.S.) through increased securitization of mortgages. These findings provide an impetus for supporting more robust analysis of climate-risk in light of forthcoming accounting rules that require an upfront accounting of forward-looking credit losses.

中文翻译：

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Underwaterwriting：从理论到美国区域抵押贷款市场的经验主义

本文为“水下承销”的概念提供了理论基础，可以将其理解为与环境暴露和气候变化影响（特别是洪水和海平面上升淹没）相关的各种信息和制度限制，这些限制影响了公司参与抵押贷款市场。Underwaterwriting表明，科学知识和本地软信息的不平衡性，以及利用这些信息的制度障碍，可能导致风险的确定可能无法准确反映长期资产绩效或信用损失。这些信息不对称可能导致风险分配反映一定程度的任意性或不准确性，这可能会导致资产搁浅并以低效的方式减少或增加市场份额，否则可能导致负面的公共外部性。与这一理论一致，本文提供的证据表明，集中的本地贷方正在通过增加抵押贷款证券化来转移东南大西洋和墨西哥湾沿岸（美国）高风险沿海地区的风险。鉴于即将出台的会计规则要求对前瞻性信用损失进行前期核算，这些发现为支持对气候风险进行更稳健的分析提供了动力。本文提供的证据表明，集中的本地贷方正在通过增加抵押贷款证券化来转移东南大西洋和墨西哥湾沿岸（美国）高风险沿海地区的风险。鉴于即将出台的会计规则要求对前瞻性信用损失进行前期核算，这些发现为支持对气候风险进行更稳健的分析提供了动力。本文提供的证据表明，集中的本地贷方正在通过增加抵押贷款证券化来转移东南大西洋和墨西哥湾沿岸（美国）高风险沿海地区的风险。鉴于即将出台的会计规则要求对前瞻性信用损失进行前期核算，这些发现为支持对气候风险进行更稳健的分析提供了动力。