SIE Format: Sweden's Accounting Data Standard Explained

SIE (Standard Import Export) is Sweden's de facto standard for accounting data interchange, created in 1992 by the SIE Group, a non-profit of Swedish accounting software vendors and professional associations. The SIE format defines tagged text files used by virtually all accounting software on the Swedish market to exchange financial data including year-end balances, period balances, and full transaction vouchers.

SIE is the backbone of accounting data portability across Sweden. Every major accounting platform supports SIE import and export, and the format is used by Skatteverket (the Swedish Tax Agency), Statistics Sweden, and the Economic Crimes Authority.

This guide provides a complete English-language reference for the SIE standard, covering:

• Origins and purpose of the standard and the organization that maintains it
• Format structure and versions, including how SIE files are organized at the technical level
• The four SIE file types and when each one applies
• SIE and the BAS chart of accounts, the standardized account framework that underpins the format
• SIE vs SAF-T, comparing Sweden's national standard against the European alternative gaining traction across Nordic and EU tax authorities
• Sweden's SIE software ecosystem, from dominant platforms like Fortnox and Visma to audit tools and tax filing integrations
• Skatteverket's digital reporting evaluation, exploring what Sweden's tax authority is considering for the future of standardized financial reporting

Whether you are an international accountant onboarding a Swedish client, a finance professional reconciling cross-border data, or a developer integrating with Swedish accounting platforms, this reference will give you the practical grounding you need to work confidently with the SIE format. The standard's origins offer essential context for understanding why it works the way it does, and that is where we begin.

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Origins and Purpose of the SIE Standard

Sweden's accounting data interchange standard did not originate from a government mandate or an international standards body. SIE, which stands for Standard Import Export, was created in 1992 by the SIE Group (Föreningen SIE-Gruppen), a non-profit collaboration between Swedish accounting software vendors and professional accounting associations. The group formed around a shared frustration: transferring accounting data between different software platforms was unreliable, expensive, and slow.

Before SIE existed, moving financial data from one Swedish accounting system to another meant manual re-entry or building custom file conversions for each software pair. An accounting firm working with clients on Visma, Fortnox, and Hogia faced three separate data formats with no common ground between them. Auditors requesting trial balances had to work within whatever export format each client's software happened to produce. SIE created a common language for Swedish accounting data: a single file format that every platform could read and write.

An important distinction for international professionals: SIE is not an official standard published by SIS (Swedish Standards Institute) or recognized under ISO. It is an industry-driven de facto standard that achieved universal adoption through voluntary implementation. Software vendors adopted SIE because their customers demanded interoperability, and that market pressure proved more effective than any regulatory requirement could have been.

SIE's reach extends well beyond private-sector accounting workflows. Several Swedish government agencies rely on the format for their operations:

• Skatteverket (the Swedish Tax Agency) uses SIE files in tax administration and audit processes
• Statistics Sweden (SCB) collects economic statistics from businesses through SIE-formatted data submissions
• Ekobrottsmyndigheten (the Economic Crimes Authority) uses SIE files in financial crime investigations

Alongside these agencies, BFN (Bokföringsnämnden), the Swedish Accounting Standards Board, sets the accounting rules and general recommendations that SIE helps implement in practice. BFN defines what Swedish businesses must record; SIE defines how that data moves between systems.

This industry-driven origin is one of SIE's most distinctive characteristics when compared to government-mandated standards like SAF-T, which was designed by the OECD and adopted through regulatory requirements across multiple European countries. Where SAF-T was built top-down for tax authority needs, SIE was built bottom-up for practitioner needs, a difference that shaped the format's technical structure from the ground up.

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How SIE Files Work: Format Versions and Structure

SIE files in versions 1 through 4 use a proprietary tagged text format. Each file is plain text, with hash-prefixed tags labeling every data element. A tag like #KONTO defines an account, #VER marks a verification (journal entry), and #TRANS records an individual transaction line. The format follows a flat, line-by-line structure where each tag sits at the start of a line followed by its associated values. This design makes SIE files compact, human-readable in any text editor, and straightforward to parse programmatically.

The format evolved incrementally across its first four versions, each adding support for more detailed accounting data. Version 4B is the most widely used specification today and represents the most feature-complete iteration of the original text-based format. It supports full transaction-level detail, dimensional accounting (cost centers, projects), and periodic balances. For most practical purposes, when Swedish accountants and developers refer to "SIE files" without specifying a version, they mean v4B.

SIE 5, released in 2018, marked a fundamental architectural shift. Rather than extending the tagged text format further, SIE 5 moved to an XML-based structure. This modernization addressed several limitations that had accumulated over the original format's decades of use. SIE 5 introduced Unicode support, replacing the older character encoding that could cause issues with international characters. It adopted English-language tags in place of the original Swedish-language tags, making the format more accessible to international developers and auditors. The XML structure also enabled foreign currency handling and the ability to reference electronic source documents directly from within the file, aligning with the broader trend toward fully digital accounting workflows.

Despite these improvements, SIE 5 adoption has been gradual across the Swedish software ecosystem. Most accounting platforms still primarily export and import using the v4B specification, which benefits from decades of universal support. Software vendors are adding SIE 5 capabilities progressively, but the transition is measured rather than abrupt. Both formats coexist in practice, with v4B handling the bulk of day-to-day data exchange.

Regardless of version, all SIE files organize their data into specific file types based on the level of detail they carry. These file types determine whether a given SIE file contains only annual balances, periodic summaries, or full transaction records.

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The Four SIE File Types

The SIE standard defines four distinct file types, each containing a different level of accounting detail. Knowing which type to request from a Swedish client or accounting system determines whether you receive summary balances or a full transaction-level audit trail.

Type	Content	Use Case
Type 1	Year-end balances	Annual report exports and year-end closings
Type 2	Period balances	Monthly or quarterly reporting and interim financial statements
Type 3	Profit centre (object-level) balances	Cost centre, department, or project-level reporting
Type 4	Full transactions and vouchers	Complete audit trail with every individual transaction, used for data migration, audit support, and forensic analysis

Type 4 is by far the most commonly requested SIE file format for accountants conducting audits or managing system migrations. Because it contains every individual voucher and transaction entry, it provides the complete financial history needed to verify balances, trace specific entries, and reconstruct the full accounting record. Types 1 and 2 serve routine reporting needs, where only aggregated balances at the year-end or period level are required. Type 3 fills a more specialized role for organizations that track their finances across cost centres, departments, or projects, providing object-level breakdowns that Types 1 and 2 do not include.

When requesting SIE files from a Swedish client or system, specifying the correct type is not optional. Requesting a Type 1 export when you actually need transaction-level detail will produce only year-end balances without any of the underlying journal entries. This is a common source of confusion for international accountants encountering the SIE file format for the first time. Always confirm the file type before initiating a data transfer or beginning audit fieldwork.

While SIE file types define what data is included in an export, the structure of the data within those files relies on a shared chart of accounts. That shared framework is the BAS kontoplan, Sweden's standardized account numbering system.

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SIE and the BAS Chart of Accounts

SIE files do not exist in isolation. Their practical value depends on a shared accounting language, and in Sweden, that language is the BAS kontoplan (BAS chart of accounts). Understanding how these two standards interlock is essential for anyone working with Swedish financial data.

The BAS chart of accounts is maintained by BAS-kontogruppen, a working group within Svenskt Naringsliv (the Confederation of Swedish Enterprise). It defines a standardized set of four-digit account numbers that map to specific transaction types across all areas of business accounting. Account 1910, for example, always refers to cash holdings. Account 2610 is designated for output VAT. Account 6210 covers telephone expenses. This consistency holds whether the business is a sole proprietorship in Malmo or a multinational subsidiary in Stockholm.

Virtually all Swedish businesses use the BAS plan, regardless of size or industry. It is not legally mandated in the way a tax code might be, but its adoption is so widespread that it functions as a de facto requirement. Accounting software sold in Sweden is built around BAS account numbers, auditors expect them, and tax filings align with them.

The relationship between SIE and BAS is symbiotic. SIE defines the file format and structure for moving accounting data between systems. BAS provides the standardized account codes that give that data consistent meaning. Together, they form the backbone of Swedish accounting data standardization.

This pairing is what makes SIE file transfers reliable in practice. When a company exports a SIE file from one accounting system and imports it into another, the receiving system can correctly interpret every transaction because both systems reference the same BAS account numbers. Account 1910 means cash in the source system, and it means cash in the destination system. No manual mapping, no ambiguity, no reconciliation headaches caused by mismatched account structures.

The combination has achieved near-total market penetration. According to the SIE Group, SIE and BAS have almost 100% implementation coverage in the Swedish bookkeeping, financial reporting, and tax administration software market. This level of adoption means that any professional working with Swedish accounting data will encounter both standards as a matched pair.

While SIE and BAS together provide a highly effective system for standardizing accounting data within Sweden, their approach is distinctly Swedish. Other European countries have pursued different paths toward accounting data interchange, and the contrast between Sweden's established standards and newer pan-European frameworks reveals important differences in philosophy and scope.

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SIE vs SAF-T: How Sweden's Standard Compares to European Alternatives

Sweden is not the only European country that needed a structured format for accounting data. Across the continent, governments and industry bodies have developed their own standards for machine-readable financial records. Understanding how SIE compares to these alternatives is essential for international professionals working across Nordic and European markets.

The following table summarizes the four major approaches:

Dimension	SIE (Sweden)	SAF-T (Norway, Portugal, others)	XAF / Auditfile Financieel (Netherlands)	GoBD (Germany)
Country / Region	Sweden	Norway, Portugal, Luxembourg, others	Netherlands	Germany
Origin / Governance	Industry-driven (SIE Group, founded by Swedish accounting bodies)	Government / OECD-driven (OECD recommendation adopted by national tax authorities)	Government-driven (Dutch Tax and Customs Administration)	Government-driven (Federal Ministry of Finance)
Format	Tagged plain text (SIE4) / XML (SIE5)	XML	XBRL GL-based XML	Framework defining requirements for digital record keeping (no single file format)
Mandate Type	De facto voluntary standard (universal adoption through industry consensus)	Legal mandate (Norway since January 2020, SAF-T v1.30 since January 2025)	Legal mandate	Legal mandate

The most important distinction in this table is the difference between industry-driven and government-driven adoption. SIE was created by accountants and software vendors to solve a practical problem: moving data between accounting platforms. SAF-T, XAF, and GoBD were created by governments and supranational bodies to solve a different problem: giving tax authorities structured access to taxpayer records for audit purposes. These different origins shaped the design priorities of each standard.

SIE optimizes for inter-system data exchange. Its file types range from annual balances (SIE1) to full transaction-level exports (SIE4), giving users flexibility in how much data they transfer between systems. SAF-T and similar government mandates optimize for regulatory compliance and audit readiness, requiring businesses to produce standardized exports on demand for tax authorities.

The question international professionals often ask is why Sweden never adopted SAF-T. The answer is timing. The OECD published its SAF-T recommendation in 2005. By that point, SIE had been in widespread use across Sweden for over a decade, with near-universal adoption among accounting software vendors. When Norway mandated SAF-T in 2020, Sweden already had a functioning, entrenched standard that served both data interchange and audit support purposes. Replacing it with SAF-T would have imposed significant transition costs on the entire Swedish accounting software ecosystem with limited incremental benefit.

Sweden is not alone in maintaining a country-specific approach. The Netherlands uses its own audit file format based on XBRL GL rather than SAF-T, as detailed in our guide to Netherlands XAF audit file requirements. Germany takes yet another path with Germany's GoBD digital record keeping standard, which defines a broad framework for how businesses must maintain digital records rather than prescribing a single export format. Even within the European e-invoicing space, formats like the Factur-X hybrid invoice format specification demonstrate that standardization remains fragmented across national boundaries.

Despite these different standards, the underlying goal is consistent across all countries: structured, machine-readable accounting data that enables automated processing, audit support, and regulatory compliance. The paths diverge, but the destination is the same.

What makes Sweden's approach distinctive is not just the standard itself but the depth of software ecosystem support behind it. Virtually every accounting platform operating in Sweden can read and write SIE files.

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Sweden's SIE Software Ecosystem

Every accounting software product sold on the Swedish market supports SIE import and export, the result of voluntary adoption driven by market demand and the standard's practical value. For anyone working with Swedish accounting data, SIE functions as the common language across the entire software ecosystem.

The major platforms that define this ecosystem each bring SIE support as a core capability:

Fortnox is the dominant SME accounting platform in Sweden, serving over 612,000 customers. SIE is the primary method for importing and exporting accounting data within Fortnox. When accounting firms onboard new clients or transfer year-end data to auditors, SIE files are the standard vehicle.

Visma is a major provider for enterprise and public sector accounting across the Nordics. Its product range, including Visma eEkonomi for smaller businesses and Visma Administration for mid-market organizations, all offer full SIE support. Larger organizations running Visma rely on SIE for inter-system data transfers and consolidation reporting.

Beyond these two market leaders, Hogia, BL (Björn Lundén), and PE Accounting all treat SIE as a core import and export capability, serving segments from large municipal operations to sole practitioner accounting firms. Microsoft Dynamics 365 and Business Central support SIE through localization modules for the Swedish market, ensuring international companies operating Swedish subsidiaries maintain compatibility with the broader Swedish accounting ecosystem.

The practical implication of this universal support is significant: Swedish accounting data is highly portable. Switching between platforms, consolidating data from multiple clients running different software, or migrating years of historical records is far more straightforward than in markets without a universal interchange format. An accounting firm handling dozens of clients across Fortnox, Visma, and BL can pull SIE exports from all of them into a single analytical tool without format conversion. Organizations exploring financial document automation benefit from this portability, since standardized data inputs reduce the friction of connecting accounting systems to downstream processing workflows.

While SIE remains the established standard and continues to serve the market well, Sweden's tax authority Skatteverket is currently evaluating whether a different digital reporting approach might better serve the country's future needs. That evaluation could reshape how Swedish accounting data moves between businesses, software, and government.

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The Future of SIE: Skatteverket's Digital Reporting Evaluation

Sweden stands at a crossroads in digital tax administration. Since 2022, Skatteverket (the Swedish Tax Agency) has been evaluating how Sweden should modernize its financial reporting infrastructure. Unlike several EU member states that have already implemented real-time or near-real-time transaction reporting, Sweden still relies on periodic filings and voluntary data standards. That evaluation is now approaching a decision point, and the outcome will shape whether SIE retains its central role or shares the stage with a government-mandated alternative.

The Three Paths Under Evaluation

Skatteverket is weighing three distinct models, each drawn from approaches already operational in other European countries.

Option 1: Adopt SAF-T. Following Norway's lead, Sweden could mandate a Standard Audit File for Tax as the required format for submitting accounting data to the tax authority. SAF-T is an OECD-originated XML schema designed specifically for tax audits and compliance reporting. If adopted, it would create a formal government-mandated audit file alongside, or potentially in place of, SIE for tax reporting purposes.

Option 2: Implement a clearance model. Modeled on systems operational in Italy and Poland, this approach would require invoices to pass through a central government platform for approval before they become legally valid. No invoice could be issued to a recipient until Skatteverket's infrastructure had verified and cleared it.

Option 3: Real-time invoice reporting. Following the approaches used in Spain and Hungary, this model would require businesses to transmit invoice data to the tax authority at or near the moment of issuance. Unlike the clearance model, invoices would not need pre-approval, but the tax authority would receive a copy of every transaction as it occurs.

How EU-Level Policy Could Narrow Sweden's Options

The EU's VAT in the Digital Age (ViDA) initiative adds an external constraint to Sweden's decision. The February 2026 commissioner inquiry into ViDA implementation signals that EU-wide digital reporting requirements may eventually mandate specific approaches for all member states. If the EU converges on a particular model, such as structured e-invoicing through the Peppol network, Sweden's freedom to chart an independent course would shrink. Skatteverket's evaluation is happening with one eye on Brussels.

What Each Outcome Means for SIE

The implications for SIE differ significantly depending on which path Sweden chooses.

SAF-T adoption presents the most direct impact on SIE's role. In a SAF-T scenario, the two standards could coexist: SIE would continue serving its current function as the universal interchange format between accounting software platforms, while SAF-T would handle the specific requirements of tax authority reporting. However, if SAF-T adoption is broad enough, software vendors might eventually consolidate around a single format, gradually reducing SIE's footprint.

A clearance model or real-time reporting system would operate at the invoice level, capturing individual transaction data as it flows between businesses. Neither approach would directly replace SIE's core function of transferring general ledger data, account balances, and period-end summaries between accounting systems. SIE and either of these models would address fundamentally different layers of the accounting data stack.

Practical Guidance for Today

Regardless of which direction Skatteverket ultimately chooses, SIE files remain the current universal standard for Swedish accounting data interchange. No timeline for mandatory adoption of any alternative has been announced. Organizations working with Swedish financial data, whether for cross-border consolidation, auditing, or software integration, should continue building their workflows around SIE today. Monitoring Skatteverket's published evaluations and any legislative proposals in the Riksdag will provide adequate lead time to adapt.

Sweden's evaluation reflects a broader European trend toward digital tax administration, where structured accounting data formats increasingly intersect with automated document processing workflows. As governments across Europe move to capture financial data earlier and in more granular detail, the intersection between structured accounting formats and tools that automate financial document processing becomes increasingly relevant. SIE may eventually share the stage with a new standard, but the underlying need for reliable, structured accounting data exchange is not going away.