Rebuild a month average

Same idea as a provisional monthly mean: arithmetic average of the business-day fixings in YYYY-MM that exist in the daily file.

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How to use this average

Type YYYY-MM (2026-09). The script averages only the daily 12-month rows that exist for that month in the live feed.

Mid-month the result is provisional — the same idea as the home “month-to-date” card. After month-end, prefer the closed file on history or year lookup.

Key: divide by the count of prints, not by 30. A TARGET holiday is a missing row, not a zero.

This tool matches searches for how the monthly Euribor average is built. Method article: how Euribor is calculated.

Why the average is the legal clock

A reset letter that names “the monthly average of month M” does not want Tuesday’s print. It wants the mean of the TARGET days in that month. This box rebuilds that mean from the same daily file the home page uses.

Key: never divide by 30 or 31. Divide by the count of published prints. A TARGET holiday is an absent row.

Daily versus that mean, on one loan: daily vs average. Essay: daily print vs monthly average.

Closed months: history. Administrator: EMMI.