A base calendar is a holiday calendar the platform offers to every organisation: a named list of closed days for one market, such as the TARGET2 settlement calendar. An organisation does not edit a base calendar. It extends one: its own calendar, created on Holiday calendars, inherits every day the base closes and adds days of its own. Filing deadlines that count business days skip those closed days, and a trading venue does not trade on them.
Base calendars is where a platform administrator publishes these calendars and keeps their closed days current. A day closed here reaches every organisation calendar and every venue that extends the base, directly or through another calendar. No organisation can remove the day from the base. A calendar stops inheriting it only when its owner points it at another parent.
Use this page when a market publishes a holiday that a base calendar does not carry, or when organisations on the platform need a base for a market the platform does not ship. Do not use it for a closure that applies to one organisation only: that organisation closes the day on its own calendar, and no other organisation sees it.
The “Base calendars” table, one row for each base calendar, with the columns “Calendar”, “Jurisdiction”, “Closed this year”, “Next closure” and “Actions”, where each row offers “Close a day”.
Steps
Skip Publish a base calendar when the calendar already exists.
Open Base calendars
Open “Platform admin”, then Base calendars. The table lists every base calendar with its “Calendar” name, its “Jurisdiction”, the days it has “Closed this year” and its “Next closure”. When you expand a row, its closed days appear grouped by year. Each day shows its reason and its source. A day closed on this page reads “Platform administrator”. A shipped day shows its dataset tag, such as “seed:target2:v1”, or for ADGM the government announcement it came from. The screen shows the kind of administrator, while the platform stores the administrator's user ID with the day and the audit trail entry names them.
Publish a base calendar
Select Publish calendar. In the sheet, enter a “Name” and choose a “Jurisdiction”: a country, or a regional code such as EU. The Console refuses a “Name” that matches an existing calendar. The jurisdiction is a label and does not change which days are closed. You can add a “Reason (optional)”, which the platform stores on the Audit trail entry for the change. That entry belongs to no organisation, because the change reaches every organisation, so no organisation's Audit trail lists it. A platform administrator reads it through the platform-wide query of the audit trail. Select “Publish calendar”. A base calendar published through this Console form extends nothing.
Publishing cannot be undone. The Console and the Platform API have no delete for a base calendar, and organisations can extend it from the moment it is published.
The calendar is offered to every organisation as soon as “The base calendar is published.” appears, even before it closes any day. An organisation that extends an empty base inherits nothing until you close days on it. A deadline calculation refuses a calendar with no closed day effective on the date it computes for, because every day would count as a business day. Publish the relevant closed days before organisations use the new base for reporting.
Close a day
On the calendar's row, select Close a day. Choose the “Date” in the calendar and choose a “Reason”: “Public holiday”, “Bank holiday”, “Settlement holiday”, “Exchange holiday” or “One-off closure”. You can also enter a “Name (optional)” for the day. The calendar offers days from 1 January 2024 through 31 December of the tenth year after the current year. The reason is a label for readers of the calendar. Every closed day counts the same way for deadlines and venues, whatever its reason.
Select “Close a day”. A second dialog names the day, for example “Close 24 Dec 2026?”. Check the date against the published source, type the date exactly as the dialog shows it, then select Close 24 Dec 2026 to add it.
What the platform ships
Four base calendars are present on every platform before an administrator adds anything:
The ADGM calendar holds announced dates only, because the UAE can move a public holiday after the rules would place it. Close each new UAE holiday on it once the date is announced. The other three calendars need a new closed day only when the published rules change or a one-off closure is declared. Their computed dates end with 2040. The shipped calendars use the identifiers target2, uk-bank-england-wales, us-federal and adgm.
How a closed day takes effect
Every day closed on this page records when the platform learned about it, and the shipped days count as known from the start. A filing deadline counts only the closed days the platform knew about when it computed that deadline. A day you close applies to deadlines computed after you close it and leaves earlier deadlines where they are, so close a missed holiday before deadlines that need it are computed.
A venue's Trading calendar tab states the rule under “Closed days”: “Days from the shared calendar shut every venue that uses it.” A day you close on a base therefore shuts every venue whose calendar chain reaches the base. Trading calendar explains what an instrument does on a day with no session. Reporting obligations describes how a deadline rule counts business days from the calendars it names.
A closed day stays on the calendar it was closed on and is never removed. The dialog states the rule: “A closed day is added, never removed. Every organisation that extends this calendar sees the day closed and cannot reopen it. A correction published later never moves a deadline that was already computed.” A base that extends another base loses the parent's days if a platform administrator changes its parent through the API, so treat a parent change as a change to every extending calendar.
One closed day on a base calendar reaches every calendar that extends it, across every organisation.
Troubleshooting
Base calendars is not in the sidebar
The entry appears only for a platform administrator. An organisation owner manages the organisation's own calendars on Holiday calendars instead.
Publish calendar stays unavailable
Publish calendar needs a free name and a jurisdiction. “A calendar with this name already exists. Choose another name.” means the name produces the identifier of an existing base calendar. A name that matches an existing calendar apart from case and spacing is refused too, such as “US Federal Holidays” for the shipped “US federal holidays”. Names that differ only in punctuation, such as “Bank holidays” and “bank-holidays”, produce the same identifier. Accented Latin letters fold to their plain letter, so “Café” gives “cafe”, and a name with no letter or digit, or with a letter or digit from another script such as Chinese, Cyrillic or Arabic, produces no identifier at all. If another administrator publishes that name while your form is open, your publish is refused. The existing calendar stays unchanged, and your form keeps its inputs. Choose another name and publish again.
A day was closed on the wrong date
The day stays closed on the base and on every calendar that extends it. Deadlines computed before the mistake keep their dates. Close the correct date as well, and tell the organisations that extend the calendar, because their deadlines computed from now on skip both days and their venues do not trade on either. The Console has no list of the calendars that extend a base, so tell every organisation on the platform. Organisations lists them.
An organisation reports a deadline that ignores a new holiday
The deadline was computed before the holiday was closed on the base. A deadline counts only the closed days the platform knew about when it computed it, so the new holiday applies to deadlines computed after it.
Frequently asked questions
Can an organisation stop inheriting a base calendar's day?
Not one day on its own. An organisation calendar that extends a base inherits every day the base closes. To stop inheriting them, the organisation changes its calendar's parent or creates a calendar that extends nothing and closes its own days.
Does a base calendar need weekend closures?
No. A filing deadline never counts Saturday or Sunday as a business day, and each venue sets its own trading week. Close a weekend day on a base only if a venue that trades at weekends must not trade on it.
Who sees a day an organisation closes?
Only that organisation. A day reaches other organisations only when it is closed on a base calendar.
API routes
The platform administration calendar endpoints are GET /api/ to list base calendars, PUT /api/ to publish or update one, and POST /api/ to add a closed day. Send If- with the PUT to refuse an id that exists. Without it, a PUT to an existing id replaces its name, jurisdiction and parent. Anyone who is not a platform administrator is refused with platform.. The Console offers none of these updates. A base that extends another base inherits its closed days. The request and response shapes are in the Platform API reference.