Build vs Buy Is the Wrong Question: A New Technology Strategy for the Tax Industry

The traditional “build vs buy” debate has long occupied boardrooms and technology teams across financial services. Should we develop our own software, tailored precisely to our needs, or buy an established solution and let someone else handle the complexity?

For organisations managing FATCA and Common Reporting Standard (CRS) tax due diligence, this familiar dilemma is increasingly outdated. Cloud computing, artificial intelligence (AI) and emerging technologies such as the Model Context Protocol (MCP) have changed the economics of software development and the way systems can work together.

The answer is becoming clearer: buy the expertise; build the connections.

As the accompanying diagram below illustrates, the better question is not whether to build or buy the entire technology stack. It is which specialist capabilities to purchase and which integrations to develop to make those capabilities work for your organisation.

Why the traditional debate no longer works

The original build-versus-buy question treats technology as one big decision. Either build everything internally or buy a complete solution from a single provider.  Both approaches have drawbacks.

Building everything in-house means taking responsibility for regulatory interpretation, due diligence rules, classification logic, reporting requirements, testing, auditability and ongoing maintenance. FATCA and CRS requirements evolve, data quality is rarely perfect, and mistakes can have significant consequences. Maintaining all this expertise internally can be expensive and distracting.

Buying everything can be equally problematic. An all-encompassing platform may offer impressive functionality, but it will not necessarily fit an organisation’s existing systems, operating model or internal processes. Customisation can become costly, integrations cumbersome and the supposedly straightforward implementation anything but straightforward.

The fundamental problem is that two very different challenges are being bundled together.  The first challenge is knowing what needs to happen: understanding regulatory obligations, applying appropriate due diligence, interpreting information and producing accurate reports. The second is making it happen within a particular organisation: connecting systems, moving data, coordinating workflows and ensuring the right information reaches the right destination.

These challenges require different capabilities. There is little reason to assume that the best provider of regulatory expertise should also dictate how every internal system operates.

Buy the expertise that is difficult to replicate

FATCA and CRS compliance are specialist disciplines. They involve much more than collecting tax residency declarations and submitting files. Organisations must establish reporting obligations, apply due diligence procedures, identify reportable accounts, manage exceptions and maintain evidence that supports their decisions.

Specialist providers invest in regulatory knowledge, tested business logic, reporting functionality and the ongoing maintenance needed to keep their solutions current.

Why recreate a complex regulatory rules engine when an experienced provider already offers one? Why develop reporting functionality, including its many edge cases, when a proven alternative is available?

Of course, buying specialist technology does not transfer regulatory accountability. Financial institutions must still assess their providers, validate outputs, maintain appropriate controls and ensure their processes meet applicable obligations.

Nevertheless, purchasing specialist expertise allows organisations to concentrate internal resources where they can make a genuine difference.

As the diagram above shows, regulatory compliance, reporting solutions and other specialist areas belong in the “buy” category where suitable, trustworthy capabilities already exist. The objective is not to own every line of code. It is to access the right expertise reliably and responsibly.

Build the integration layer that differentiates you

If specialist expertise is something to buy, where should organisations build? 

The answer is the integration layer: the data pipelines, transformations, APIs and workflows that connect specialist solutions to the organisation’s own technology landscape.  Every institution has a different combination of core systems, onboarding platforms, customer databases, data warehouses, document repositories and internal processes. Even organisations with similar business models rarely have identical architectures.

One institution might need to connect onboarding information to a due diligence platform, route exceptions to a review team and transfer approved results into its reporting environment. Another may need to reconcile records across multiple legacy systems before information is ready for processing.  These requirements are specific to the organisation. They reflect its systems, people, processes and operational priorities.

This is where internal development can create real value.  Rather than building another compliance engine, organisations can develop the connections that make purchased expertise useful in their particular environment. They retain control over how information flows, how exceptions are handled and how technology supports their operating model.

Think of the specialist solution as the engine and the integration layer as the transmission. A sophisticated engine is of limited use if it cannot deliver power to the wheels. Equally, a beautifully engineered transmission cannot compensate for an engine that does not do its job.  The goal is to make the complete system work, not to manufacture every component.

Cloud and AI change the economics

Cloud computing has made this approach considerably more practical. Modern infrastructure, managed services and APIs allow organisations to develop targeted integrations without investing in an entirely new technology estate.

Artificial intelligence adds further momentum. AI-assisted development can help teams write connectors, transform data, generate tests, document interfaces and troubleshoot integration problems. Work that once required substantial development effort can often be completed more quickly.

That does not mean AI should be trusted to create production-grade compliance logic without oversight. Generated code can contain errors, and sensitive financial data demands rigorous security, testing and governance.

The opportunity is more practical: use AI to reduce the effort involved in connecting systems, while relying on appropriately validated specialist solutions for complex regulatory functions.

This changes the economics of the build-versus-buy decision. When integrations become easier and cheaper to develop, there is less justification for purchasing an oversized platform simply because connecting separate products once seemed too difficult.

There will still be awkward legacy interfaces, inconsistent data and undocumented dependencies. Technology, unfortunately, has not yet invented a universal cure for systems built decades ago by people who have since retired.  But the barriers to creating a more flexible architecture are falling.

MCP: connecting capabilities rather than duplicating them

The Model Context Protocol (MCP) is another development worth watching. It provides a standardised way for compatible AI applications to discover and interact with external tools and data sources.

Consider a tax due diligence case involving inconsistent residency information. An AI-enabled assistant could, subject to appropriate permissions, retrieve case details, consult approved guidance, request information from a specialist compliance platform and help prepare an exception summary for human review.

MCP can provide a common mechanism for connecting the assistant to these capabilities, rather than requiring every AI application to implement a separate bespoke integration.

It does not replace the underlying compliance platform, guarantee interoperability or make AI decisions inherently reliable. Access controls, data protection, audit trails and human oversight remain essential, particularly when handling sensitive financial information.

Its significance lies in the broader principle: systems can expose specific capabilities for other applications to use, reducing the need to duplicate functionality.

That reinforces the architecture illustrated in the diagram above. Buy the specialist expertise, build the connections and retain control over how those capabilities fit into your organisation.

A better question for technology leaders

This does not mean buying everything and building nothing. Some organisations will have genuinely differentiating intellectual property that justifies internal development. Others will have requirements that demand carefully designed bespoke components.  The important thing is to evaluate each capability separately.

Buy regulatory expertise where specialist providers can maintain it effectively. Buy proven reporting solutions where they meet your requirements. Build the integrations, workflows and data pipelines that reflect your organisation’s particular needs. Govern the complete architecture through appropriate security, testing, monitoring and assurance.

For FATCA and CRS professionals, regulatory obligations will continue to evolve, data landscapes will remain complicated, and expectations around reporting quality and evidence will remain high.  The solution need not be another attempt to build or buy an entire technology universe.

Cloud computing makes flexible architectures more accessible. AI helps accelerate development. MCP offers new ways to connect tools and services. Together, these developments make the traditional all-or-nothing debate increasingly difficult to defend.

Perhaps the better question is simply this:

Which expertise should we buy, and which connections should we build to make that expertise work for us?

For tax due diligence technology, that is not just a better question. It is a more practical blueprint for the future.

If you’d like to see how TAINA can simplify and streamline your CARF and CRS compliance journey, we’d be delighted to request a demo.

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