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Guide for Affordable Care Act (ACA) Information Returns (AIR) Submission Composition and Reference Guide

Table of Contents

Publication 5258 — Guide for Affordable Care Act (ACA) Information Returns (AIR) Submission Composition and Reference Guide · 2026-10-03 edition · updated 2026-10-04 · United States

Section 1 Introduction 2

1.1 | Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 | Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 | Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.4 | Related Documents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Section 2 Interface Overview 5

2.1 | ISS-UI Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 | ISS-A2A Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Section 3 Composing IRS ACA Information Returns Transmission 8

3.1 | Namespace and Prefix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.2 | Guidelines for Composing IRS Form Data File . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3 | IRS Form Data File Naming Convention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.4 | Structure of IRS Form Data File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.4.1 | Manifest Transmission XML Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.4.2 | Uniquely Identifying Transmissions, Submissions, and Records . . . . . . 15

3.4.3 | Computing Checksum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Section 4 Transmitting IRS ACA Form Data File and Retrieving Acknowledgment via the ISS-UI Channel 20

4.1 | Transmitter Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2 | Transmitting UI Files to IRS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2.1 | Sample Manifest File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2.2 | Sample Form Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.3 | Retrieving Acknowledgment from IRS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

TABLE OF CONTENTS

4.4 | Transmitter IRS Form Data File Specification. . . . . . . . . . . . . . . . . . . . . . . . . 32

4.5 | Transmitting Information Returns to IRS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.5.1 | Validation of IRS Form Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.5.2 | Processing of IRS Form Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.6 | Retrieving Status of the Transmission through UI. . . . . . . . . . . . . . . . . . . . . . 34

4.7 | IRS Error Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.8 | UI Channel TY2017, TY2018, TY2019, TY2020, TY2021, TY2022,TY2023, TY2024, TY2025 and TY2026 Schemas. . . . . . . . . . . . . . 38

4.9 | 4.9 Calculate AttachmentByteSizeNum for TY2017,TY2018, TY2019, TY2020, TY2021, TY2022, TY2023, TY2024, TY2025 and TY2026. . . . . . . . . . . . . . . 38

Section 5 Transmitting IRS ACA Form Data File and Retrieving Acknowledgment via the ISS-A2A Channel 40

5.1 | Message Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.2 | Basic SOAP Message Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.2.1 | Creating the SOAP Envelope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.2.2 | SQL Injection in the SOAP Message. . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5.3 | SOAP Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.3.1 | WS-Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.3.2 | ACA Transmitter Business Header Elements . . . . . . . . . . . . . . . . . . . . . 53

5.3.3 | ACA AIR Transmission Manifest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.4 | SOAP Body. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.4.1 | Message Attachment File Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.4.2 | Message Attachment Content Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.5 | ISS-A2A Web Services Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.5.1 | Overview of Transmission and Submission. . . . . . . . . . . . . . . . . . . . . . . 56

5.5.2 | IRS-ACA Submit Transmission Request Message. . . . . . . . . . . . . . . . . 58

5.5.3 | IRS-ACA Retrieve Acknowledgement Request Message. . . . . . . . . . . . 60

5.5.4 | A2A Channel TY2017, TY2018, TY2019, TY2020,TY2021, TY2022, TY2023, TY2024, TY2025 and TY2026 Schema/WSDL Guidance. . . . . . . . . . . 62

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters III

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Section 6 Identifying Transmissions and Records 64

6.1 | Identifying the Transmission Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.2 | Identifying the Transmission Status (Acknowledgement) . . . . . . . . . . . . . . . 66

6.3 | Receipt ID or UTID as Basis for Uniquely Identifying Transmissions and Records. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

6.3.1 | Uniquely Identifying Forms 1094 within a Transmission. . . . . . . . . . . . . 70

6.3.2 | Uniquely Identifying Forms 1095 within a Transmission. . . . . . . . . . . . . 71

6.4 | Identifying Records with Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.5 | Corrections and Replacements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

6.5.1 | The Correction Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

6.5.2 | Transmitting Corrections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

6.5.3 | Transmitting Form 1094-C Corrections (Authoritative Transmittals Only).75

6.5.4 | Transmitting Forms 1095-B or 1095-C Corrections . . . . . . . . . . . . . . . . 76

6.5.5 | Transmitting Forms 1094-C and Forms 1095-C Corrections. . . . . . . . . 76

6.6 | Rejected Transmissions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.6.1 | Transmissions Rejected by IRS Portal. . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.6.2 | Transmissions/Submissions Rejected by AIR. . . . . . . . . . . . . . . . . . . . . 77

6.7 | Replacement Process - Transmitting Replacements. . . . . . . . . . . . . . . . . . . 78

6.7.1 | Replacement Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.7.2 | Replacement Submission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Section 7 Data Mapping for ISS-UI Services/ISS-A2A Web Services 86

7.1 | Data Mapping – Message Data Boundary. . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.2 | Data Mapping – Form Data Boundary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Section 8 Example ISS-A2A Web Service Messages 106

8.1 | Transmitter Services SOAP Message Elements. . . . . . . . . . . . . . . . . . . . . . 106

8.1.1 | IRS-ACASubmitService SOAP Request Message – Manifest Header (ACAGetTransmitterBulkRequestService.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . 106

8.1.2 | IRS-ACASubmitService SOAP Request Message – Form Data File (ACAGetTransmitterBulkRequestService.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . 108

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters IV

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8.1.3 | IRS-ACASubmitService SOAP Response Message (ACAGetTransmitterBulkRequestService.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . 112

8.1.4 | IRS-ACAAckngService SOAP Request Message (ACAGetTransmitterBulkRequestStatus.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . . 113

8.1.5 | IRS-ACAAckngService SOAP Response Message – Manifest Header (ACAGetTransmitterBulkRequestStatus.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . . 113

8.1.6 | IRS- ACAAckngService SOAP Response Message – Error Data File (ACAGetTransmitterBulkRequestStatus.wsdl). . . . . . . . . . . . . . . . . . . . . . . . . . 114

Section 9 General Philosophy on Data Elements in XML Schemas 116

Section 10 Validating a Transmission against XML Schema 118

10.1 | Structure of Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

10.2 | Validation of Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

10.3 | Validating the Transmission Envelope Including Contents. . . . . . . . . . . . . 119

10.4 | How Errors are Reported. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Section 11 Reporting Business Rule Validation Errors 123

11.1 | Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

11.2 | Data Validation and Error Reporting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

11.2.1 | Processing Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

11.2.2 | Error and Business Rule Library. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Section 12 SOAP Fault Response Messages 126

12.1 | ISS-Portal Error Codes and Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Section 13 Appendix A - Acronyms and Abbreviations 142

Section 14 Appendix B - AIR Transmission Checklist (A2A) for TY2026 144

Section 15 Appendix C - IR Transmission Checklist (UI) for TY2026 150

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters V

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List of Tables

Table 3-1: Prefix and Target Namespaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Table 3-2: Transmission Manifest XML Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 4-1: Forms to XML Schema File Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Table 4-2: Transmission Processing Status Included in Acknowledgement. . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Table 5-1: Characters not allowed due to SQL Injection Concerns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Table 5-2: IRS Authorized Certificate Issuing Authorities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Table 5-3: Transmitter Business Header Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Table 5-4: Transmission SOAP Message Binding – SOAP Request Message Header. . . . . . . . . . . . . . . . . . . 58

Table 5-5: Transmission SOAP Message Binding – SOAP Request Message Body. . . . . . . . . . . . . . . . . . . . . 59

Table 5-6: Transmission SOAP Message Binding – SOAP Response Message Header. . . . . . . . . . . . . . . . . . 59

Table 5-7: Transmission SOAP Message Binding – Soap Response Message Body. . . . . . . . . . . . . . . . . . . . 59

Table 5-8: Status Request SOAP Message Binding – SOAP Request Message Header . . . . . . . . . . . . . . . . . 60

Table 5-9: Status Request SOAP Message Binding – SOAP Request Message Body. . . . . . . . . . . . . . . . . . . 61

Table 5-10: Status SOAP Message Binding – SOAP Request Message Header. . . . . . . . . . . . . . . . . . . . . . . . 61

Table 5-11: Transmission SOAP Message Binding – Soap Response Message Body. . . . . . . . . . . . . . . . . . . 61

Table 6-1: Transmission Type Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 6-2: Unique Submission Identifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 6-3: Unique Record Identifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 7-1: Form 1094-1095 B and C Transmission SOAP Request Header – ACA Business Header . . . . . . . 87

Table 7-2: Form 1094-1095 B and C Transmission SOAP Request Manifest Header. . . . . . . . . . . . . . . . . . . . 87

Table 7-3: Form 1094-1095 B and C Transmission SOAP Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 7-4: Form 1094-1095 B and C Acknowledgement SOAP Request to check the Status of the Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Table 7-5: Form 1094-1095 B and C Transmission SOAP Response Header. . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Table 7-6: Form 1094-1095 B and C Transmission SOAP Response Header – ACA Business Header. . . . . . 91

Table 7-7: Form 1094-B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Table 7-8: Form 1095-B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Table 7-9: Form 1094-C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 7-10: Form 1095-C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Guide for ACA Information Returns Submission Composition and Reference Guide. . . . . . . . . . . . . . . . . . 123

Table 12-1: Portal Error Codes (Fault Codes) for Tax Years 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025 and 2026. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters. . . . . 149

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters VI

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List of Figures

Figure 2-1: External Clients and IRS AIR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 3-1: Structure of IRS Form Data File [B and C]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 3-2: Unique Transmission Identifier (UTID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 3-2: Unique Transmission Identifier (UTID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 3-3: Unique Submission Identifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 3-4: Unique Record Identifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 4-1: ISS-UI Channel Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 4-2: ISS-UI Channel Transmission Submission Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 4-3: ISS-UI Channel Transmission Submission Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 4-4: Sample Manifest File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 4-5: Sample 1094-1095 B Form Data File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 4-6: Transmission Status Search Page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 4-6b: Transmission Status Search Page (UTID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 4-7: A2A Check Status using UTID Request. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 4-8: A2A Check Status using UTID Response to Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 4-9: ISS-UI Channel Transmission Status Results Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 4-10: Example of Acknowledgement via ISS-UI Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 4-11: Error Data XML File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 5-1: Basic SOAP Message Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 5-2: High Level Form schema structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Figure 5-3: ACA Binding – ACAGetTransmitterBulkRequestService.wsdl. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Figure 5-4: ACA Binding – ACAGetTransmitterBulkRequestStatus.wsdl. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Figure 6-1: Identifying the Transmission Status Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figure 6-3: Sample AIR ISS-A2A Transmission Intake Response Message . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 6-4: Sample AIR ISS-UI Transmission Intake Response Message. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Figure 6-5: Submission Id is Required for Every Form 1094 in the Transmission. . . . . . . . . . . . . . . . . . . . . . . 70

Figure 6-6: Form 1094-C XML Schema Including RecordId. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Figure 6-7: Reference Records to be Corrected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 6-8: Replacing a Rejected Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 6-9: Visual depicting the first-rejected submission in a chain of rejections that should be replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Guide for Electronically Filing ACA Information Returns for Software Developers and Transmitters VII

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▸Contents — Publication 5258 — Guide for Affordable Care Act (ACA) Information Returns (AIR) Submission Composition and Reference Guide

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