Skip to main content

Does ESEF Report Size Matter?

ESEF Reporting
ESEF annual report sizes - does it matter?
4 min read

Jackie Whitworth

Global Marketing Manager
Published: 4 January 2021
Last Updated: 4 January 2021

Long ago, size didn’t matter for the annual report of a company—apart from the person who signs off the budget, of course. Each year the investor heard a heavy thump on their door mat—the glossy first edition annual report in 250 gsm. More recently, the PDF has replaced print runs, so what happened to file size?

Trends in PDF file sizes have varied enormously over the years. In many cases, however, the investor got left behind and ignored in favour of big graphics and print heavy colour palettes. 

If an investor wanted to print a section, it was at the expense of the majority of his or her ink cartridge. Unoptimised PDFs became the norm, but they left download misery for the rest of us.

Nearly half of all users quit in three seconds if they have to wait for the page to load. The size appreciated by Google is actually fairly small—around 1 MB.  With pagination of many reports over 300 pages and slick double page graphics, PDF sizes are high. In a sample of 2,500 reports in 2019, the highest topped 134 MB!

But this is old news—or is it? With the dawn of ESEF approaching (or dusk in respect of potential delays!), the annual report  is now becoming a digital experience using XHTML. Does the size of the PDF reflect the size of the XHTML? What is too big? And if the file size is too big, who should scream first? The flash graphics or the patient investor waiting in download hell? Let’s take this apart.

File size under the ESEF mandate

Many regulators are now stating a file size limit of 100 MB max. This is the size of the unzipped file, not just the XHTML report. There are other items you need to consider which have to be in the zip file, such as:

  • Catalogue
  • Taxonomy package
  • XBRL® files

These are relatively small, but together they all add up. The addition of a viewer will enhance the user’s experience, but this will add around 1.5 MB to your zip file. It’s a worthwhile addition, so make sure if you want to add it, you can.

How do you stop a filing or download nightmare? How can you reduce the size of your report? Read on for tips for designers can use to optimise their file size.

For the designer in InDesign

Here are things the designer needs to do to reduce the final file size in Adobe® InDesign®:

  • Avoid empty paragraphs to achieve extra space in your document
  • Make sure all content has a style name attached
  • Make sure you crop all your images to the correct size, 100% and RGB
  • Review your font embedding in SVGs
  • Review your SVGs carefully, and make sure you are using the optimal points to create a shape
  • Think carefully if all of your images are necessary
  • Make sure you have reduced your images to 72 dpi—the resolution for websites
  • Try a "Save as" at the end of your process—this can cut down the file size considerably as it can clear out unnecessary code

IDML export is a file size detox, but here are some other things you can do before exporting:

  • Remove any unused objects
  • Delete unused styles
  • Delete anything left on paste boards or any extra master pages

From IDML to XHTML: The Workiva way

Workiva will work hard with the IDML from InDesign in additional ways—such as those listed below—to make sure your report is as optimised as possible. Our InDesign plugin will also help validate content.

  • Your paragraph styles become tags like <p>, <h1>, <li>
  • Character styles become inline like <span class =”bold”>
  • Object styles become <div>, <section>
  • Table styles become <td>, <th>

The code Workiva produces is clean and compact, which helps with download size and speed. Essentially, everything not necessary is removed.

Now that the report doesn’t land in one large envelope on the doormat, and the PDF is about to be a filing thing of the past, follow the simple rules in this blog to make sure your ESEF report is ideal for your filing requirements and your stakeholders.

Check out this on-demand webinar if you interested in learning more about how to create excellent design using content from the Workiva platform.


XBRL® is a trademark of XBRL International, Inc. All rights reserved. The XBRL® standards are open and freely licensed by way of the XBRL International License Agreement. Adobe and InDesign are either registered trademarks or trademarks of Adobe in the United States and/or other countries.

About the Author
Jackie Whitworth

Global Marketing Manager

Jackie specialises in designed reporting together with the ESEF mandate at Workiva. She is also the co-founder of PortAlchemy, a financial data consumption platform of listed companies in the EU. Prior to this, Jackie was involved with the marketing and servicing of content management systems, annual report production and has been responsible for the maintenance of investor relations websites for major companies.

Online registration is currently unavailable.

Please email events@workiva to register for this event.

Our forms are currently down.

Please contact us at

Our forms are currently down.

Please contact us at