iXBRL with Seahorse

1. Abstract

ESMA (European Securities and Markets Authority) is the EU’s financial markets regulator and supervisor.

ESMA has developed the regulatory technical standards (RTS) which specify the European Single Electronic Format (ESEF) that is the reporting format in which issuers, whose securities are admitted to trading on EU regulated markets, must prepare their annual financial reports to facilitate accessibility, analysis and comparability of the annual financial reports themselves.

Consolidated financial statements issued by entities on the EU regulated market, need to be, in fact, marked up using iXBRL tags.

2. Content

2.1 iXBRL

iXBRL is an open standard that allows a single document to provide data in both human-readable and machine-readable format.  It is used to prepare financial statements in a format that provides the structured data that regulators and analysts require. The preparers have full control over the layout and presentation of their report.

iXBRL uses xHTML to place XBRL (Extensible Business Reporting Language) tags “in line” with the visible text.

xHTML (eXtensible HyperText Markup Language) takes traditional HTML and “adds” the XML that provides machine-readable metadata. xHTML is used by most of the web pages: the HTML layer includes the basic text, colors and images, while the metadata includes all the information that defines the text.

Finally, the iXBRL is a filing format that merges human-readable HTML file with the XBRL tags that give meaning to the figures and statements in a format that can be understood by a computer.

2.2 Seahorse

Seahorse is an online application which can convert Microsoft Excel, Microsoft Word, XHTML and EPUB documents related to the annual financial statement into iXBRL

All outputs from Seahorse are validated against all the relevant technical standards and the filing rules specific to each reporting program. This includes the production of extensions and report packages as specified by ESMA for ESEF and UKSEF filings.

The application, therefore, guarantees full compliance with technical and regulatory standards.

2.3 Tag

A tag is defined by a Concept and a Context.

Concept is represented by:

  • Label: is the name/description of the tag
  • Type: identifies the attributes of the tag (e.g. Monetary/Text, Credit/Debit)
  • Sign: specifies whether the sign (+/-) of the tag should be inverted 
  • Dimension: represent further details


  • Period type: it can be duration or instant, it depends on the type of information (e.g. balance sheet accounts or income statement accounts)
  • Period: month/year
  • Unit: represents the currency 
  • Accuracy: represents the accuracy of the value reported
  • Scale: represents the scale (e.g. units, thousands, …)

Following some of the major features in Seahorse that “help” the user in the tagging process:

  • Bulk Review 
  • View calculation
  • View duplicate tags
  • Validate document

2.3.1 Bulk Review

The bulk review function allows users to quickly review in bulk the tag suggestions.

Seahorse displays the suggestions for the table’s line items, along with information on the sign, type of period and the confidence value for the suggested line item as a percentage. The user can flag the checkboxes and confirm the line items in bulk.

2.3.2 View calculation

The calculation viewer can be used to examine any calculations which have failed validation and identify the tags. In this way the user is facilitated in the correction of the errors.

2.3.3 View duplicate tags

Seahorse has a functionality which allows to show duplicate tags. Duplicate tags occur when the same tag is created multiple times within a document. They can be inconsistent duplicates if these multiple occurrences have different reported values or consistent duplicates if the values are the same. Based on the different jurisdictions the user has to solve/ remove the duplicated tags.

2.3.4 Validate document

The validate document action displays the errors in the document and the reasons why the filing failed the necessary criteria and requirements to produce the iXBRL.

Once the Document has been tagged and has passed the validations, it is possible to produce and download the Ixbrl document.

Seahorse has also an automated tag-selection engine using machine-learning to take into account tagging selections made in previous and other filings. In this way it is also possible to copy the company’s prior-year tags, reducing effort for subsequent years.