Excess Share Insurance is a wholly owned subsidiary of American Share Insurance, the credit union-owned private deposit insurer that pioneered excess share insurance for credit unions. ESI was chartered to standardize that coverage as demand grew, and it writes excess share insurance for both federally and privately insured credit unions.

ESI sells the coverage through two programs. Double Cover adds up to $250,000 of protection above a credit union's primary coverage limits, while Custom Cover extends protection up to $10,000,000 above those limits for specific members and larger institutional accounts. The coverage is relationship-based: it requires no system integrations and keeps deposits at the credit union rather than splitting them across institutions, which lets a credit union retain larger balances for local lending.