Royal Decree extends deadline for thematic investment deduction certificates

For the reformed thematic investment deduction, which applies to fixed assets acquired or created from 1 January 2025 onwards, the taxpayer must in principle enclose a specific certificate with the tax return, showing that the investment is included in the relevant investment list and meets the applicable conditions. This deduction is based in law on Article 69/1 ITC 92; the certification requirement is further governed by Article 69/3 ITC 92 and means, in principle, that the certificate is enclosed with the return in order to claim the deduction. 

As we already explained in our previous article, a longer filing period had already been provided as a transitional measure for applying for these certificates, until 30 June at the latest. With the publication of the Royal Decree of 16 June 2026, a further administrative tolerance has now been introduced to address the practical difficulties arising from the fact that the certification procedure is not yet fully operational. For fixed assets acquired or created between 1 January 2025 and 31 December 2026, no certificate needs to be enclosed with the return in order to apply the increased thematic investment deduction where obtaining a certificate is not yet practically possible. 

This tolerance is not a free pass, however. The taxpayer must keep a file available for the tax authorities showing that all reasonable steps were taken to establish that the investment appears on the relevant investment list and meets the applicable conditions. This could be a report by an internal or external expert, a substantiated decision or note, or a quote or invoice that explicitly refers to the relevant features of the investment. If, at the time the return is filed, it is already possible to apply for a certificate but no decision has yet been taken, the application must also actually be submitted, and the application documents can then serve as additional evidence. 

Importantly, this temporary arrangement does not mean that no certificate will be required in the end. After 31 December 2026, a positive certificate must still be available for submission, failing which the right to the increased investment deduction lapses. At the same time, the deadline for applying for the certificate has been extended: for the investments concerned, a period of twelve months from the last day of the taxable period now applies, with 31 December 2026 as the new final date instead of 30 June 2026. 

Where do things stand now? 

In Flanders, the Flemish Energy and Climate Agency ('VEKA') is responsible for issuing the certificates for energy and environmental investments. 

For energy investments, the VEKA web application has been operational since 8 May 2026. Pending the definitive cooperation agreement between the federal and regional authorities, no certificates are being issued for the time being. Where relevant, applications can already be prepared and submitted through the web application. We do recommend, however, that you mainly prepare the application in substance, using VEKA's provisional manual (published on 19 May 2026), and that you do not yet submit it formally as long as the cooperation agreement is not definitive. VEKA does indicate that, should the definitive cooperation agreement give rise to further changes, it will be possible to amend or supplement an application that has already been submitted. Even so, caution remains advisable, given the questions of interpretation and application that still exist. 

In particular, the requirement for a prior energy study creates additional uncertainty as well. It was initially assumed that a list of recognised experts would be published and that the authorities would set out a number of matters on which the energy expert would have to give an opinion. However, VEKA's provisional manual shows that no list of recognised energy experts will be published, at least for now. VEKA will decide whether the expert report meets the prescribed rules, and in the absence of an energy study no certificate can be obtained, and therefore no investment deduction. For investments in Flanders that already took place before this manual was published, the question therefore arises whether the energy study, where one exists at all, will be found sufficient…

For investments included on the environmental investment lists, VEKA states that the portal for applying for certificates will go live at a later stage. Certificates for investments in carbon-emission-free transport must, by contrast, be applied for with the FPS Mobility and Transport. General information and the application procedure are available on the FPS Mobility and Transport website, under the heading "Thematic investment deduction". 

For the other regions, the picture is less developed. For the Walloon Region, the regional authorities state that companies which made an eligible investment in 2025 and are approaching the filing deadline must submit a declaration of intent to apply for the certificate. This declaration of intent must contain at least the date of acquisition, the amount of the investment and the category under which the investment falls, and can be sent to deductionfiscale.energie@spw.wallonie.be. 

It nevertheless remains uncertain whether such a declaration of intent will be regarded by the federal tax authorities as an effective application for a certificate, and therefore whether the statutory assessment period would start to run from the submission of that declaration of intent. 

For the Brussels-Capital Region, too little practical information appears to be available at this stage to determine with certainty how and when applications for the certificates concerned can be submitted. 

If you have questions about the administrative requirements, or would like to discuss the options for your business, get in touch with our BDO expert.