The capitalization deposit is the structural feature with no bank counterpart, and it explains behavior members occasionally see. 12 USC 1782(c)(1)(A)(i) requires each insured credit union to "pay to and maintain with the National Credit Union Share Insurance Fund a deposit in an amount equaling 1 per centum of the credit union's insured shares." The amount is adjusted to track changes in insured shares, annually for a credit union with total assets of $50 million or less and semi-annually for a larger one, under 1782(c)(1)(A)(iii). Under 1782(c)(1)(B) the deposit is returned if the institution's insurance coverage is terminated or it converts to coverage from another source.
That is a genuinely different arrangement from an insurance premium. A premium is paid and gone; this deposit stays on the credit union's own balance sheet as an asset. It is why the fund's finances are described in terms of an equity ratio rather than only reserves, and why a fund surplus has somewhere to go.
Surplus is returned, and the statute makes it mandatory rather than discretionary. 12 USC 1782(c)(3)(A) provides that the Board "shall" effect a pro rata distribution to insured credit unions after a calendar year in which any federal loans to the fund and interest on them have been repaid, the fund's equity ratio exceeds its normal operating level, and its available assets ratio exceeds 1.0 percent. Subparagraph (B) sets the amount as the maximum that does not push either ratio back below those thresholds. The distribution runs to the credit unions themselves rather than to individual members, so a member sees it only indirectly, in whatever the institution does with the money.
Coverage is applied to the member, not to the account, and the aggregation step comes first. 12 USC 1787(k)(1)(B) directs that in determining the amount payable to a member, "there shall be added together all accounts in the credit union maintained by that member for that member's own benefit, either in the member's own name or in the names of others." Opening a second share account or a share certificate at the same credit union therefore adds nothing to the ceiling, because the balances are combined before the limit is applied. What changes the answer is holding money in a genuinely different capacity, and that is where the next paragraph starts.
The categories that multiply coverage come from regulation, and the statute says so. 12 USC 1787(k)(1)(C) gives the Board authority to "define, with such classifications and exceptions as it may prescribe, the extent of the share insurance coverage provided for member accounts, including member accounts in the name of a minor, in trust, or in joint tenancy." So the treatment of a joint account, a payable-on-death account, or an account an adult holds for a child is a matter of NCUA rules rather than of the Federal Credit Union Act itself. The practical consequence is that these rules can change without Congress acting, and one such change is in progress: the NCUA's trust-account rules are being brought into line with the FDIC's, and until that takes effect the two agencies do not compute trust coverage identically. The detail sits on the credit union page, which is its single home.
The guarantee is not universal across credit unions. A small number of state-chartered institutions carry private share insurance instead of the federal kind, and the NCUA states plainly that private coverage is not backed by the full faith and credit of the United States. Confirming which kind an institution carries is a step worth taking before a large balance depends on the answer, and the credit union page covers how to check.