Tax Retention Documents

Overview

Tax Retention Documents (Comprobantes de Retención) are official certificates issued when taxes are withheld from payments in Mexico. These documents are mandatory for various business transactions including contractor payments, professional services, and rental income.

What are Tax Retention Documents?

Tax retention documents serve as proof that taxes have been withheld and paid to SAT on behalf of the recipient. They are essential for:

Tax compliance: Proving taxes were properly withheld
Income declarations: Supporting deductions and credits
Audit requirements: Maintaining proper tax records
Business relationships: Transparency between parties

Legal Framework

Tax retention in Mexico is governed by:

Income Tax Law (ISR): Defines retention requirements
VAT Law (IVA): Sets VAT retention rules
SAT Guidelines: Operational procedures and formats
CFF (Fiscal Code): General tax obligations

Digital Structure

Tax retention documents are XML-based with specific structure:

<retenciones:Retenciones>
  <retenciones:Emisor RfcEmisor="ABC123456789"/>
  <retenciones:Receptor RfcRecep="XYZ987654321"/>
  <retenciones:Periodo MesIni="01" MesFin="01" Ejerc="2024"/>
  <retenciones:Totales MontoTotOperacion="10000.00" 
                       MontoTotRet="1000.00"/>
  <retenciones:ImpRetenidos>
    <retenciones:ImpRet BaseRet="10000.00" 
                       Impuesto="001" 
                       MontoRet="1000.00"/>
  </retenciones:ImpRetenidos>
</retenciones:Retenciones>

Available Formats

Tax retention documents can be retrieved as:

XML: Original structured data with all fiscal information
PDF: Human-readable certificate for printing and sharing
Metadata: Extracted key fields for integration

Types of Tax Retention

Common Retention Scenarios

Professional Services

Retention Rate: 10% ISR + 10.67% VAT

Legal services
Consulting fees
Professional advice
Technical services

Contractor Payments

Retention Rate: Variable based on service

Construction work
Maintenance services
Installation projects
Repair services

Rental Income

Retention Rate: 10% ISR

Property rental
Equipment leasing
Vehicle rental
Commercial spaces

Transportation

Retention Rate: 4% ISR

Freight services
Logistics
Courier services
Cargo transport

Tax Types Subject to Retention

Tax Code	Tax Name	Common Rate	Description
`001`	ISR (Income Tax)	10%	Most professional services
`002`	IVA (VAT)	10.67%	Services with VAT retention
`003`	IEPS	Variable	Special products and services

Extracting Tax Retention Documents

Basic Extraction Request

{
  "subject": {
    "identifier": "ABC123456789"
  },
  "credentials": {
    "SAT": {
      "type": "USERNAME_PASSWORD", 
      "username": "ABC123456789",
      "password": "CIEC_PASSWORD"
    }
  },
  "options": {
    "informationType": "TAX_RETENTION",
    "direction": "INBOUND",
    "period": {
      "from": "2024-01-01",
      "to": "2024-01-31"
    }
  }
}

Advanced Filtering Options

{
  "filters": {
    "emitter": {
      "operator": "equals",
      "value": "GACJ841128A87"
    }
  }
}

Key Data Fields

Essential Retention Information

Parties Information

Withholding Agent (Emisor):

RFC and business name
Address and contact information
Retention authority designation

Recipient (Receptor):

RFC and taxpayer name
Tax regime information
Address details

Financial Details

Payment Information:

Total operation amount
Taxable base for each tax
Retention rates applied
Total retained amounts

Tax Breakdown:

ISR retention details
VAT retention (if applicable)
Other applicable taxes

Period and Dates

Time Information:

Payment period covered
Retention certificate issue date
SAT validation timestamp
Fiscal year reference

Direction Types

Understanding direction is crucial for proper accounting treatment.

Direction	Description	Accounting Impact
`INBOUND`	Taxes retained from payments you received	Tax Credit - Reduces your tax liability
`OUTBOUND`	Taxes you retained from payments to others	Tax Liability - Must be paid to SAT

Integration Examples

Processing Inbound Retention Certificates

// Process retention certificates received (tax credits)
async function processInboundRetentions(extractions) {
  const retentions = await getCompletedDocuments(extractions, 'TAX_RETENTION');
  
  for (const retention of retentions) {
    const retentionData = await parseRetentionXML(retention.xmlContent);
    
    // Record as tax credit
    await recordTaxCredit({
      period: retentionData.period,
      withholdingAgent: retentionData.emitter.name,
      isrRetention: retentionData.taxes.isr.amount,
      vatRetention: retentionData.taxes.iva.amount,
      totalCredit: retentionData.totalRetention,
      certificateId: retentionData.uuid
    });
    
    console.log(`Processed retention credit: $${retentionData.totalRetention}`);
  }
}

Processing Outbound Retention Obligations

// Process retention certificates issued (tax obligations)
async function processOutboundRetentions(extractions) {
  const retentions = await getCompletedDocuments(extractions, 'TAX_RETENTION');
  
  for (const retention of retentions) {
    const retentionData = await parseRetentionXML(retention.xmlContent);
    
    // Record as tax obligation
    await recordTaxObligation({
      period: retentionData.period,
      recipient: retentionData.receptor.name,
      baseAmount: retentionData.operationAmount,
      retainedAmount: retentionData.totalRetention,
      dueDate: calculateDueDate(retentionData.period),
      status: 'pending_payment'
    });
    
    console.log(`Recorded retention obligation: $${retentionData.totalRetention}`);
  }
}

Monthly Retention Report

// Generate monthly retention summary
async function generateRetentionReport(month, year) {
  const period = {
    from: `${year}-${month.padStart(2, '0')}-01`,
    to: `${year}-${month.padStart(2, '0')}-31`
  };
  
  // Get both inbound and outbound retentions
  const [inboundRetentions, outboundRetentions] = await Promise.all([
    extractRetentions('INBOUND', period),
    extractRetentions('OUTBOUND', period)
  ]);
  
  const report = {
    period: `${year}-${month}`,
    credits: {
      count: inboundRetentions.length,
      totalISR: sumRetentionsByTax(inboundRetentions, '001'),
      totalVAT: sumRetentionsByTax(inboundRetentions, '002'),
      totalAmount: sumTotalRetentions(inboundRetentions)
    },
    obligations: {
      count: outboundRetentions.length,
      totalISR: sumRetentionsByTax(outboundRetentions, '001'),
      totalVAT: sumRetentionsByTax(outboundRetentions, '002'),
      totalAmount: sumTotalRetentions(outboundRetentions)
    },
    netPosition: calculateNetPosition(inboundRetentions, outboundRetentions)
  };
  
  return report;
}

Compliance Requirements

Legal Obligations

Retention Payment Deadline: Retained taxes must be paid to SAT by the 17th of the following month.

For Withholding Agents

Responsibilities:

Calculate correct retention rates
Issue retention certificates within 30 days
Pay retained taxes to SAT by deadline
File monthly retention declarations

Penalties for non-compliance:

Late payment: 1.13% monthly interest
Missing certificates: Fines up to $15,000 MXN
Incorrect retention: Additional penalties

For Recipients

Rights and obligations:

Request retention certificates
Apply credits in tax declarations
Keep certificates for 5 years
Report discrepancies to SAT

Benefits:

Reduce tax liability
Improve cash flow
Simplified tax compliance

Best Practices

Common Issues and Solutions

Missing Retention Certificates

Problem: Expected certificates not found in SAT systemPossible Causes:

Withholding agent hasn’t issued certificate
Incorrect RFC information
Processing delays in SAT system

Solutions:

Contact withholding agent for certificate status
Verify RFC spelling and format
Wait 24-48 hours for SAT processing
Use alternative documentation if necessary

Incorrect Retention Amounts

Problem: Retention amounts don’t match expectationsPossible Causes:

Wrong retention rate applied
Calculation errors
Different taxable base interpretation

Solutions:

Verify current retention rates with SAT
Review taxable base calculations
Consult with tax advisor for complex cases
Request correction from withholding agent

XML Parsing Errors

Problem: Cannot process retention XML dataPossible Causes:

Corrupted file download
Invalid XML structure
Missing required fields

Solutions:

Re-download document from SAT
Validate XML against SAT schemas
Use robust XML parsing libraries
Implement error handling for malformed data

Integration with Accounting Systems

Automatic Journal Entries

// Create accounting entries for retention certificates
async function createRetentionJournalEntry(retentionData, direction) {
  const entries = [];
  
  if (direction === 'INBOUND') {
    // Tax credits from received retention certificates
    entries.push({
      account: 'ISR_RECEIVABLE',
      debit: retentionData.taxes.isr.amount,
      description: `ISR retention credit - ${retentionData.emitter.name}`
    });
    
    if (retentionData.taxes.iva.amount > 0) {
      entries.push({
        account: 'VAT_RECEIVABLE', 
        debit: retentionData.taxes.iva.amount,
        description: `VAT retention credit - ${retentionData.emitter.name}`
      });
    }
    
    entries.push({
      account: 'ACCOUNTS_RECEIVABLE',
      credit: retentionData.totalRetention,
      description: `Total retention credit`
    });
  } else {
    // Tax obligations from issued retention certificates
    entries.push({
      account: 'ACCOUNTS_PAYABLE',
      debit: retentionData.totalRetention,
      description: `Retention obligation - ${retentionData.receptor.name}`
    });
    
    entries.push({
      account: 'ISR_PAYABLE',
      credit: retentionData.taxes.isr.amount,
      description: `ISR retention obligation`
    });
  }
  
  await createJournalEntry({
    date: retentionData.issueDate,
    reference: retentionData.uuid,
    entries: entries
  });
}

Next Steps

SAT API Quickstart

Start extracting retention documents from SAT

CFDI Invoices

Learn about invoice extraction and processing

Use Cases

See retention compliance automation examples

Troubleshooting

Resolve common retention processing issues

Getting Started

SAT API Reference

Document Types

Use Cases

Webhooks

Overview

What are Tax Retention Documents?

Types of Tax Retention

Common Retention Scenarios

Professional Services

Contractor Payments

Rental Income

Transportation

Tax Types Subject to Retention

Extracting Tax Retention Documents

Basic Extraction Request

Advanced Filtering Options

Key Data Fields

Essential Retention Information

Direction Types

Integration Examples

Processing Inbound Retention Certificates

Processing Outbound Retention Obligations

Monthly Retention Report

Compliance Requirements

Legal Obligations

Best Practices

Common Issues and Solutions

Integration with Accounting Systems

Automatic Journal Entries

Next Steps

SAT API Quickstart

CFDI Invoices

Use Cases

Troubleshooting

Getting Started

SAT API Reference

Document Types

Use Cases

Webhooks

​Overview

​What are Tax Retention Documents?

​Types of Tax Retention

​Common Retention Scenarios

Professional Services

Contractor Payments

Rental Income

Transportation

​Tax Types Subject to Retention

​Extracting Tax Retention Documents

​Basic Extraction Request

​Advanced Filtering Options

​Key Data Fields

​Essential Retention Information

​Direction Types

​Integration Examples

​Processing Inbound Retention Certificates

​Processing Outbound Retention Obligations

​Monthly Retention Report

​Compliance Requirements

​Legal Obligations

​Best Practices

​Common Issues and Solutions

​Integration with Accounting Systems

​Automatic Journal Entries

​Next Steps

SAT API Quickstart

CFDI Invoices

Use Cases

Troubleshooting

Overview

What are Tax Retention Documents?

Types of Tax Retention

Common Retention Scenarios

Tax Types Subject to Retention

Extracting Tax Retention Documents

Basic Extraction Request

Advanced Filtering Options

Key Data Fields

Essential Retention Information

Direction Types

Integration Examples

Processing Inbound Retention Certificates

Processing Outbound Retention Obligations

Monthly Retention Report

Compliance Requirements

Legal Obligations

Best Practices

Common Issues and Solutions

Integration with Accounting Systems

Automatic Journal Entries

Next Steps