What Bank of N.T. Butterfield & Son Ltd told the SEC could break it.

Single-product credit concentration: residential mortgage portfolios were 70.6% of the Group's loan book at end-2025, concentrated in the same small island markets the bank operates in.

“Accordingly, there is no dependence or concentration on a single product in these markets outside of the residential mortgage portfolios, which comprised 70.6% of the Group's loan book as at December 31, 2025”

Key markets (Bermuda, Cayman) sit in the hurricane belt; severe weather, earthquakes, and rising sea levels threaten operations and the collateral behind a loan book that is ~70% island residential mortgages.

“The key markets in which we operate including Bermuda and the Cayman Islands, as well as our and our customers' business, operations and financial conditions, are subject to the risks associated with severe weather conditions (including among others tropical storms, hurricanes, floods and tornadoes), earthquakes, rising sea levels and other natural disasters”

Banking operations are concentrated in three small offshore markets: Bermuda (43% of FY2025 net revenue), Cayman (31%), and Channel Islands/UK (18%) — more exposed to a downturn in these islands than diversified competitors.

“Our banking operations are concentrated in Bermuda, the Cayman Islands and the Channel Islands and the UK, and we serve customers in these markets.”

Cayman depends on US imports, so recent US tariff increases pass through to local inflation (estimated 1.9% year-end 2025) — a tariff-to-island-economy channel affecting the bank's market.

“Given the Cayman Island's dependence on the US for imports, it is expected that the recent increases in US import tariffs will have a pass through effect on local inflation, resulting in estimated year-end inflation of 1.9% in 2025.”