Calendars and holidays. Holidays per calendar. The scheduler skips them; feed business dates and T-1 tokens follow them. Calendar US is built in for 2026 and 2027; FIRM is your own. Key: calendar + holiday. One file: the header attributes, then the records. The business date the data is for (YYYY-MM-DD). Your firm code, shown on Data › Feeds (e.g. F00012). Who produced the file (vendor or system name). When the file was produced (UTC). The number of record elements. A file whose count does not match is refused (F004): it was probably cut short. delta: only the records in the file change, and action="delete" removes one. full: the file is complete (this data set has no inactivation: full behaves as delta). One calendars and holidays record. Elements may appear in any order. Calendar code, e.g. US or FIRM. Part of the key. A code: letters, digits, "_", "." or "-", up to 20. Part of the key. The date the calendar is closed. Part of the key. An ISO date, YYYY-MM-DD. Part of the key. What the holiday is. Text, up to 120 characters. upsert (insert or update by key) or delete (removes the record; a security or account is inactivated, never deleted).