About Us – Optimise Accountants

CPD Training & White Label Tax Services for US & UK Accounting Firms

The UK accounting services market continues its robust expansion, valued at £38.5 billion in 2025, with sustained growth driven by increasing demand for specialised international tax expertise. Yet many accounting firms face a critical challenge: while globalisation creates unprecedented opportunities for cross-border services, the complexity of maintaining dual-qualified expertise across the US and UK tax systems often forces firms to refer valuable clients elsewhere.

Optimise Accountants are CPD accredited and proud of that fact, so we are confident that we bring to you the very best UK & US taxation training and support whenever you require it. We continually update our CPD activities to ensure that you stay ahead of the tax law game compared to your competitors, while providing the best advice to your clients.

At Optimise Accountants, we specialise in CPD training for accountants and white-label tax services to help firms expand their income streams, retain clients, and stay compliant with international regulations. Founded in 2003 by Simon Misiewicz (FCCA, ATT, EA, MBA), our team of dual-qualified US & UK experts combines decades of cross-border experience with a proven track record in training and outsourced tax solutions for accounting firms and advisors.

The modern accounting landscape presents both opportunities and challenges for firms seeking to serve internationally mobile clients. With advisory services comprising 45.1% of market value in the UK accounting sector, the demand for specialised tax knowledge has never been higher. However, maintaining current expertise across multiple jurisdictions requires significant investment in continuing education and professional development.

Professional bodies recognise this complexity through their rigorous CPD requirements. US Enrolled Agents must complete 72 hours of continuing education every three years, including a minimum of 16 hours annually with at least 2 hours in ethics. Meanwhile, UK professionals face equally demanding standards, with ACCA members required to complete 40 annual CPD units, of which 21 must be verifiable through documented evidence.

These requirements reflect the increasing sophistication of compliance, where expertise in ITIN applications, FIRPTA withholding, W-8BEN-E treaty planning, and expat tax returns has become essential for serving globally mobile clients effectively.

Feature / Approach	Our CPD & White-Label Services	Traditional Approaches (Hiring or Referring Clients Away)
Upfront Cost	Low – pay-per-case or annual CPD fee	High hiring costs or revenue lost when referring clients away
Compliance Expertise	Dual-qualified US & UK tax experts (EA, FCCA, ATT)	Dependent on recruitment quality or third-party providers
CPD/CE Accreditation	Included with all training programmes	Rarely included
Client Relationship Control	All work is branded under your firm’s name	Risk of clients switching to external providers
Scalability & Flexibility	Start small, scale on demand	Limited by staff capacity or external provider availability
Revenue Retention	100% of tax fees stay in-house	Significant income is lost when referring clients away

Simon Misiewicz Cross Border Tax Specialist

Simon Misiewicz isn’t just another tax professional—he’s one of the few people qualified on both sides of the Atlantic to help accountants handle even the most complex US–UK cross-border tax cases.

• Dual US–UK Tax Credentials:
  Simon is an Enrolled Agent (EA) with the IRS and Certified Acceptance Agent (CAA), enabling him to handle US tax filings, ITINs, and IRS representations. On the UK side, he’s FCCA (Fellow Chartered Certified Accountant) and ATT (Association of Taxation Technicians) qualified, bringing deep UK tax knowledge under HMRC rules.

• 20+ Years’ Experience:
  Simon has worked with hundreds of US and UK tax professionals—from small accountancy firms to large practices—helping them deliver compliant, efficient, and profitable cross-border tax solutions.

• Specialist in Cross-Border Tax Compliance:
  He regularly handles cases involving US Forms 1040, FBAR, 5471, 8938, PFIC 8621 filings, UK SA106, SA109, foreign tax credits, pension transfers, and double tax treaty positions.

Our Mission

Our goal is to provide international tax training for accountants and fully branded white-label services so firms can confidently handle complex issues in-house. Whether you want to train your team through CPD/CE-accredited courses or outsource cross-border cases under your own brand, we deliver practical, revenue-generating solutions for modern accounting firms.

What our experts offer your accounting firm

CPD Training for Accountants (US & UK)

Our training ensures your team stays ahead of international regulations while earning CPD/CE accreditation.

Essential Support Training (CPD Hours Per Course)

Our foundational training modules cover core international tax competencies that every modern accounting firm should offer. The ITIN Application Mastery course provides comprehensive guidance on navigating IRS requirements for Individual Taxpayer Identification Numbers, including common pitfalls and optimisation strategies for processing. Similarly, our FIRPTA Compliance and Refunds support equips participants with the knowledge to confidently handle Foreign Investment in Real Property Tax Act requirements.

The W-8BEN-E Treaty Planning course addresses one of the most complex areas of compliance, covering treaty benefit analysis, limitation on benefits provisions, and proper documentation requirements. Each module combines theoretical knowledge with practical case studies drawn from real-world scenarios, ensuring participants can immediately apply their learning to client situations.

Advisory Partnership Development (CPD Hours)

For firms seeking to develop more sophisticated international tax capabilities, our advisory-level training covers advanced topics including dual-residency planning, treaty shopping prevention, and complex expat scenarios. These courses are particularly valuable for firms serving high-net-worth clients or businesses with substantial cross-border operations.

Participants learn to navigate the intersection of the US and UK tax systems, understanding how changes in one jurisdiction can create opportunities or challenges in the other. This level of expertise enables firms to move beyond basic compliance services into higher-value advisory work that commands premium fees.

Full Integration Programs (CPD Hours)

Our comprehensive training programs are designed for firms committed to building internal centres of excellence for international tax services. These intensive programs combine multiple specialist areas with practical implementation guidance, enabling participants to develop complete offerings for mobile clients.

The curriculum includes advanced case study analysis, client communication strategies for complex international matters, and ongoing support for implementing new support lines. Participants also receive access to our resource library, including template documents, process guides, and regular updates on regulatory changes affecting cross-border compliance.

White-Label Tax Services for Seamless Client Support

Recognition of expertise limitations should not result in lost clients or reduced service quality. Our support enables firms to maintain client relationships while delivering specialist international support under their own brand identity. This approach addresses a common industry challenge: while outsourcing work may seem like an obvious solution, many firms hesitate due to concerns about protecting client relationships and maintaining service quality control.

Protecting Client Relationships Through Branded Excellence

Our white-label approach ensures that all client communications, deliverables, and ongoing support appear to originate directly from your firm. Clients receive the same experience they expect from your organisation, while your firm benefits from access to specialised expertise that would be prohibitively expensive to develop internally.

This model proves particularly valuable for complex cases involving dual-residency scenarios, international business restructuring, or multi-jurisdictional compliance requirements. Rather than referring these opportunities elsewhere, firms can retain the client relationship while leveraging our invisible support structure to deliver.

Flexible Service Delivery Models

Recognising that different firms have distinct needs and client bases, we provide flexible engagement models tailored to your specific requirements. Pay-per-case arrangements provide cost-effective access to specialist expertise for occasional international matters, while annual retainer agreements offer predictable costs and priority access for firms with regular cross-border requirements.

For firms serving significant numbers of mobile clients, our embedded support model creates the appearance of internal expertise while maintaining cost efficiency. This approach enables smaller firms to compete effectively with larger organisations that may have dedicated departments.

All deliverables are fully branded under your firm’s name, protecting client relationships while adding new revenue streams.

Market Opportunity and Revenue Generation

• Decades of experience in US and UK tax systems

• CPD/CE-accredited training for accountants

• Flexible outsourcing models with pay-per-case options

• Proven ROI with firms retaining clients previously referred elsewhere

The convergence of increasing international business activity and complex regulatory requirements creates substantial revenue opportunities for firms that are well-positioned to serve cross-border clients effectively. Market analysis indicates growing demand for advice, driven by regulatory complexity, digital taxation initiatives, and the continued globalisation of business operations.

Firms successfully integrating international capabilities report significant improvements in client retention and average fee levels. The ability to handle complex cross-border matters internally, rather than referring work elsewhere, not only preserves existing client relationships but also often leads to expanded offerings that meet the client’s entire tax and advisory needs.

ROI Through Client Retention and Service Expansion

The financial impact of developing international capabilities extends beyond direct fee generation. Firms often discover that clients requiring support also have sophisticated needs in other areas, including corporate advisory services, estate planning, and business structuring. By maintaining these relationships through comprehensive support, firms position themselves for expanded advisory engagements across multiple service lines.

Cost analysis comparing internal capability development with outsourced support consistently demonstrates the efficiency advantages of our training and white-label models. Rather than investing in recruiting specialist staff, maintaining costly professional development programs, or building internal systems for occasional international work, firms can access world-class expertise while preserving capital for core business development activities.

Common Pitfalls in International Tax Work & How We Solve Them

Missed Deadlines & Penalties

Challenge: IRS and HMRC filing deadlines are strict; missing filings result in penalties.
Solution: We provide CPD training and white-label fulfilment with built-in deadline tracking.

Double Taxation Risks

Challenge: Without treaty knowledge, clients often pay tax twice.
Solution: Our experts apply US/UK tax treaty provisions accurately through training and outsourcing.

Lost Client Relationships

Challenge: Referring work away risks clients permanently moving to external providers.
Solution: We deliver all work fully branded under your firm, keeping loyalty in-house.

Limited Staff Expertise

Challenge: Few firms have dual-qualified U.S. and U.K. tax specialists on staff.
Solution: CPD training upskills your team quickly, and white-label support fills knowledge gaps.

Revenue Leakage

Challenge: Firms lose fees when clients are sent elsewhere for help.
Solution: Retain full revenue by keeping both compliance and advisory work in-house.

Implementation and Getting Started

The successful integration of international tax capabilities requires careful planning and a phased implementation. We work closely with partner firms to develop customised approaches that align with their existing client base, growth objectives, and operational constraints.

Initial engagement typically begins with assessment of current client needs and identification of opportunities for service expansion. This analysis helps prioritise training investments and development activities, ensuring maximum impact from professional development initiatives.

For firms seeking immediate capability enhancement, our white-label services provide instant access to specialist expertise while internal teams develop competency through our programs. This dual approach enables firms to capitalise on current opportunities while developing long-term capabilities for sustained growth.

The combination of structured CPD training and flexible support provides a comprehensive solution for firms committed to developing international tax expertise. Whether your goal is basic compliance capability or sophisticated advisory services, our programs provide the foundation for sustainable growth in this expanding market segment.

Ready to expand your firm’s tax capabilities? Contact us to discuss customised CPD training programs and white-label options that align with your specific requirements and growth objectives.