Prismm (Wunderwood Corporation d/b/a Prismm), an estate orchestration infrastructure platform serving banks and credit unions, has announced the launch of its Deposit Mortality Index (DMI) — a first-of-its-kind measurement tool designed to provide financial institutions with deeper insight into the strength, stability, and long-term trajectory of their deposit portfolios. The index has been used to score all 8,429 federally insured U.S. banks and credit unions.

The DMI was developed by Prismm Founder and CEO Martha Sylla Underwood, author of The Death of Deposits. It helps banks and credit unions identify hidden maturity risk within their deposit bases and uncover opportunities to strengthen customer relationships before assets leave the institution.

Built on Prismm's proprietary methodology, the DMI report transforms publicly available data — including FDIC branch deposits, U.S. Census demographics, Federal Reserve holdings data, and Social Security Administration (SSA) life tables — into actionable intelligence that institutions can use to guide strategic planning.

Unlike conventional deposit reporting, which typically focuses on balances and historical trends, the Deposit Mortality Index measures the resilience of an institution's deposit base by evaluating the factors that influence whether deposits are likely to remain in place as ownership changes over time. The result is a practical benchmark for assessing future deposit risk and identifying new retention opportunities.

The scale of the challenge is significant. An estimated $124 trillion in U.S. household wealth is projected to transfer through 2048, and approximately 70 percent of inherited balances leave the incumbent financial institution. This generational shift — widely referred to as the Great Wealth Transfer, driven by the aging of the Baby Boomer demographic — has made deposit retention an increasingly pressing concern for financial institutions. The 2023 failures of Silicon Valley Bank, Signature Bank, and First Republic Bank, in which rapid deposit outflows played a central role, further underscored the importance of understanding deposit stability for bank executives and regulators.

"Banks and credit unions have never had a way to measure the future health of their deposits until now," said Martha Sylla Underwood, Founder and CEO of Prismm. "The Deposit Mortality Index gives executives a completely new perspective by revealing risks and opportunities that traditional reporting simply cannot see. As wealth changes hands over the coming decades, institutions that understand the maturity of their deposits will be far better positioned to preserve deposits and retain relationships for generations to come."

Each DMI report provides a composite score, a national tier classification, and a national rank among all scored institutions, along with a detailed breakdown of the growth, demographic, and portfolio dynamics shaping the institution's deposit outlook. The analysis highlights where mortality-driven deposit runoff may emerge, identifies the underlying factors contributing most to risk, and pinpoints which actions could have the greatest impact — giving leadership teams a focused starting point for planning without requiring them to independently parse complex actuarial or public-data inputs.

The index was calibrated once across the full national distribution and then frozen, ensuring that scores remain comparable across institutions and over time. The complete methodology, assumptions register, and change log are available upon request.

Interested institutions can learn more or request their report at getprismm.com/dmi.