BBK: pre-1999 Frankfurt fixings (1948-1998)

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Added Deutsche Bundesbank (BBK) as a historical provider covering the pre-euro period that ECB cannot serve.

Scope

Pre-1999 only. BBK's post-1999 series mirrors ECB (same Frankfurt fixing feed) and was evaluated and rejected on that basis in an earlier audit. This addition reverses that decision specifically for the 1948-1998 window, where BBK is one of very few authoritative sources.

Source

• Dataflow: BBEX3, filtered to SERIES_TYPE=AA (historical Frankfurt fixings)
• Date range: 1948-06-21 through 1998-12-30
• Local backfill: 209,128 rates loaded and spot-checked

Currencies (18)

USD, GBP, JPY, CHF, FRF, ITL, NLG, BEF, LUF, DKK, NOK, SEK, ESP, PTE, ATS, FIM, IEP, CAD

Per-currency start dates reflect postwar reintroduction of quoting:

Currency	Start	Note
USD	1948-06-21	Day after DEM introduction
GBP, CHF, NLG, BEF, LUF, DKK, NOK, SEK	1949-12-21	Exchange resumption
FRF, ITL, IEP	1950-51
CAD	1953
ATS	1954
ESP	1963
JPY	1969
FIM	1972

All series end 1998-12-30 (euro cutover).

Rate direction

Bundesbank publishes quotes as "N foreign = X DEM", the inverse of ECB style. Records are stored as { base: foreign, quote: DEM, rate: scaled-per-1-unit }, matching the NBG precedent already in the codebase.

Multipliers

14 of 18 currencies are quoted per-100 (ATS, BEF, CHF, DKK, ESP, FIM, FRF, JPY, LUF, NLG, NOK, PTE, SEK) or per-1000 (ITL). Multipliers are hardcoded from verified cassette data and cross-checked at runtime by parsing the German BBK_TITLE field. A mismatch raises.

Legal

Bundesbank Nutzungsbedingungen section 4.1 permits personal and commercial redistribution with attribution: "Quelle: Deutsche Bundesbank" / "Source: Deutsche Bundesbank".

Terms: https://www.bundesbank.de/de/startseite/benutzerhinweise/nutzungsbedingungen-fuer-den-allgemeinen-gebrauch-der-website-763554