Tax changes for 2027: what actually changes for accountants and SMBs

In short: 2027 brings no new taxes and does not raise the general rates. What it does bring is a broader RESICO, fines for not having the Buzón Tributario (SAT’s tax mailbox), a program to reduce fines and surcharges, limits on some deductions for large companies and, above all, more enforcement.

The 2027 Economic Package was presented on September 8, 2026. The Chamber of Deputies approved it on October 14 and the Senate committees on October 21, without changes. Until it is published in the Official Gazette of the Federation (DOF), what follows is the approved proposal, not the final law.

1. RESICO: the cap rises to 5 million

Individuals will be able to file under the Simplified Trust Regime (RESICO) with income of up to 5 million pesos a year (today it is 3.5 million). For legal entities the proposed cap is 50 million.

If you were close to the limit and worried about being pushed out, review your income projection for 2027 before changing regimes.

→ Read more: RESICO 2027: the cap rises to 5 million

2. Buzón Tributario: fines start on January 1

The obligation to have the Buzón Tributario enabled already existed, but the penalty was on hold. From January 1, 2027, SAT can fine anyone who does not have it enabled or does not have valid contact methods $3,850 to $11,540.

→ Read more: Buzón Tributario: fines from January 2027

3. Regularization: fewer fines and surcharges

The 2027 Revenue Law (LIF) proposes reducing fines, surcharges and collection costs on tax liabilities from 2025 and earlier years. During the debate in the Chamber of Deputies the 300 million income cap was removed, so the benefit would open up to more taxpayers.

→ Read more: Tax regularization 2027

4. Large companies: limits on deductions

• The limit for deducting net interest drops from 30 % to 20 %.
• New limits on carrying forward tax losses for companies with income above 50 million.
• The optional regime for groups of companies is eliminated.
• Payments abroad are deducted in the fiscal year in which they are paid and the withholding is remitted.

5. Interest: lower withholding

The annual withholding on interest would go from 0.90 % to 0.68 %.

6. What doesn’t make the headline: more enforcement

Accountants’ associations agree that 2027 brings more scrutiny than taxes. SAT cross-checks your CFDI faster and faster against your electronic accounting, your returns and the lists of non-compliant taxpayers (69 and 69-B). Errors that used to go undetected for months now arrive as an invitation letter.

What to do before January:

1. Enable the Buzón Tributario for every RFC you handle.
2. Check that your suppliers are not on the 69-B list.
3. Confirm that every installment payment has its payment complement.
4. Reconcile your CFDI against what you reported in 2026.

How Clauhub helps

Clauhub Fiscal connects to SAT with your e.firma, downloads up to five years of your CFDI and checks your suppliers every day against the 69 and 69-B lists, cancelled invoices and payments without a REP. That way you reach 2027 with everything reconciled. Discover Clauhub Fiscal

Sources

• Chamber of Deputies, approval of the 2027 Income Tax (ISR) reform (Oct 14, 2026).
• Senate Finance and Legislative Studies Committees (Oct 21, 2026).
• 2027 Economic Package, SHCP (Sep 8, 2026).

We will update this when the final text is published in the DOF.