ESEF and File Sizes

When you convert your annual report to iXBRL, you may experience a quite large discrepancy in sizes between the PDF version and the converted file. This is because the xHTML format which is needed for an iXBRL file doesn't handle image compression as well as PDF does.

Luckily, there are a couple of things you can do to make sure that your ESEF package stays nice and small. The tips given in this article are a great place to start.

·       What are the size limits on an ESEF report?

There is no limit to the size of an ESEF file, which means they can be of any size depending on the number of images, the number of pages, etc. However, while ESMA doesn’t place a limit on ESEF file sizes, many regulators have a limit on the size of the file you are allowed to submit (which is usually around 100MB). Different local authorities may set different requirements, which means you have to check these restrictions locally before publishing your report.

·       How can we reduce the size of the final file?

As a rule of thumb, if you want to reduce the size of your ESEF package the first step should be to reduce the size of your PDF. This can be achieved by reducing either the image quality or the number of images in the file.

While the images are a good place to start, there are a few other ways you can reduce the size of your ESEF package. We’ve compiled a list of tips you can discuss with your designer/design agency to make sure the final ESEF file is nice and small:

  1. All images should be correctly cropped and displayed in 100% and RGB
  2. Reduce the dpi of images to 72
  3. Don’t overload the report with unnecessary images
  4. Avoid empty paragraphs when working in InDesign
  5. All content needs a style name when working in InDesign
  6. When creating shapes in InDesign, make sure you use optimal points
  7. Review the font embedding in your SVG’s
  8. Remove unused objects before exporting
  9. Delete unused styles before exporting
  10. Delete anything left on pasteboards and any extra master pages.

If you have any questions regarding the size of your converted file, please find more information in this article ESEF - Size Matters! or contact us at