Portfolio-level exposure: you are one line in a book

Every limit described so far is measured inside one account. Institutions run a second set measured across all of them at once, and those are the ones that produce changes nobody in the account can explain.

The book-level caps mirror the account-level ones, one layer up. Total lending value supported by any single issuer across every borrower. Total exposure to a sector. Total exposure to any one custody arrangement. Total size of the lending book relative to the funding available to support it. Each has a ceiling, expressed as a percentage of the whole.

When one of these binds, the institution has to reduce exposure across a population rather than in one file. The cheapest instrument for that is the schedule: cut the advance rate on the affected class and every borrower holding it contributes to the reduction proportionally. It is administratively trivial, it is defensible, and it requires no conversation with anyone.

Two features make this hard to see from inside an account. The reduction arrives as a schedule version, indistinguishable from a revision prompted by anything else, so there is no marker recording which cause produced it. And the timing follows the institution's own reporting cycle rather than the market: a ceiling is usually measured at a period end, so the cut can land days or weeks after the exposure that caused it was built, against a backdrop that no longer explains anything.

The revision that removed your capacity may have been caused by portfolios you have never seen, held by people you will never meet, at an institution doing arithmetic on a total you are a rounding error inside.