How to Reach the Close of the 2026 NIS Report with Your Data in Order

For most Mexican companies, the NIS report for fiscal year 2025 was a leap into the void with a safety net. The standards were new, the processes didn’t exist, and CINIF knew it — which is why NIS B-1 came with two built-in reliefs. Both Scope 3 and the Sustainable Investment indicator could be omitted. With no historical comparatives to defend and no external auditor questioning every figure, the first report required work, but could be handled internally without too much complication.

In 2026, everything changes.

What changes in fiscal year 2026

The second NIS report operates under different rules, and the differences are not minor. To begin with, 2026 data will have to be presented alongside 2025 data, because year-over-year comparison is mandatory. If the first report had errors, inconsistencies, or weak estimates, they will be exposed the moment the numbers appear side by side.

Scope 3 can no longer wait either. Indirect value-chain emissions — the hardest to measure, and in many sectors the largest share of the real footprint — are mandatory to report for the current fiscal year. There is no exemption, no extension.

What happens in 2027? The ISSA 5000 standard takes effect in December of this year, which means the financial statements for fiscal year 2026 will be the first to reach an external auditor with instructions to review sustainability information with the same rigor applied to the accounts. The difference between a well-documented data point and a number pulled from a spreadsheet with no traceability will show.

The first mistake is starting to collect data too late

The NIS report isn’t done in December — it’s done all year round. Every energy invoice, every fleet trip, every purchase from a supplier generates data that will be needed in January to calculate the environmental indicators. If that data wasn’t properly collected at the time, it doesn’t disappear: it can be recovered, estimated, or reconstructed from whatever is available. But doing it after the fact is an enormous effort. It means chasing old invoices, asking suppliers for information after they’ve already closed the quarter, applying estimates where there should have been real measurements, and documenting every methodological decision so the auditor understands why the data looks the way it does.

Even so, the result isn’t the same. A data point collected at the time, with a clear source and full traceability, is a data point that can withstand an audit. A data point reconstructed in December from approximations is a data point that has to be defended.

Fiscal year 2026 is six months underway. The data for January through June has already been generated. The question is whether someone is collecting it correctly — or whether it will need to be reconstructed in December.

The most common mistakes being made right now

The problems that show up in the NIS report’s environmental indicators are usually not errors of regulatory interpretation or complex calculation — they’re process errors:

• Data collected from different sources each year, with no fixed criteria
• Scopes defined differently depending on who does the calculation
• Outdated emission factors applied to actual consumption
• Supplier information arriving incomplete, late, or in incompatible formats

These are the same four patterns that repeat company after company, and most don’t notice them until they try to present the comparatives or answer an auditor’s questions.

Knowing about them in advance changes the picture completely. Not because they’re hard to fix, but because almost all of them have a solution if identified while the fiscal year is still open. Once the year closes, the options narrow to justifying the errors or redoing the entire process.

There’s still time to get it right

The midpoint of 2026 has just arrived. For most companies, that means there’s still time to review how environmental data is being collected, identify the indicators that carry the most risk, and set up the processes that will be needed when the auditor arrives.

It isn’t a question of resources or advanced technology. It’s a question of knowing exactly where the most common mistakes are — and what to do about them before the fiscal year closes.

And for that, we’ve prepared a guide covering solutions to the most common mistakes in the NIS report’s environmental indicators. Everything needed to close out 2026 with your data in order.

Download the guide here

Fiscal year 2026 is already underway, but there’s still time to get it right.