Our Leadership

Linus Ostberg

Partner

Linus started his professional career in London in the private client space more than 16 years ago. In those years Linus spent time in Sweden and California. Linus has had the privilege of setting up and leading a private client team at a top 10 accounting firm and one of the big four.

Linus deals with a variety of clients and tax matters, from European based US families with succession and estate planning needs to international entrepreneurs moving to the US.

Being qualified in multiple jurisdictions Linus is trusted by his clients to sit at the centre of their tax worlds with a unique ability to make the complicated simple.

Linus’ aim with any client is to understand their current and long-term goals to help them achieve the best and most economical outcome based on their specific fact pattern.  

Outside of work Linus likes to spend time exploring the countryside with his son, wife, and horse.

Gus Sinclair

Partner

Gus, alongside Linus, has spent the past seven years setting up private client offerings for some of the market’s larger firms.

Gus typically focuses on corporate stakeholders and spends time not only understanding their personal goals but the long-term business ambitions to ensure both tax strategies are aligned.

Gus believes the alignment of a business and their shareholders, whilst having an advisor that understands both, is essential to effective advice. Naturally, successful stakeholders have complicated financial worlds that Gus sits centrally to ensuring all tax strategies are aligned.

Gus strongly believes in the value of people and prioritises having a quality team working on clients to ensure they are effectively managed day-to-day.

Gus and his wife regularly travel back to their roots in Scotland for some fresh air out of the city.

Robyn Limmer

Partner

Robyn started her career back in the mid 80’s when the Big 4 were the Big 8.  Robyn has always worked in the international tax space, specialising in advising prominent dual US/UK taxpayers navigate the highly complex double tax regime. In latter years, Robyn was proud to lead one of the larger private client advisory firms in London, ultimately transitioning the business into one of the Big four accounting firms in 2021.

Having had the privilege of running an entrepreneurial fast growing professional services firm, Robyn brings a wealth of business experience to OSCO and is well placed to support the partners as they grow the business. Robyn has always had a focus on excellent client service, technical expertise and a strong team spirit, and will continue that focus at OSCO aligning with the firm’s ethos.

In her spare time Robyn likes nothing better than to be outdoors hiking, skiing or playing tennis.

Joshua Tennant

Partner

Josh has spent his professional career focusing on trust and estate taxation for the international market in and out of London. Being dual-qualified in the US and UK as well as an affiliate STEP member, Josh is uniquely placed to deal with complex fact patterns.

Josh has a heavy focus on clients with a connection to the US and is well known for advising US and international families on their succession strategy whilst also assisting with all the families reporting obligations across both jurisdictions.

Josh leads the trust and estate offering at OSCO and has spent his career building strong relationships with similarly focused advisors and trustees. Josh’s experience and network allows him to confront and resolve the unique cases posed by clients with international complexities.

Given his estate focus, Josh takes a long-term view with clients to ensure efficiencies are managed from the outset whilst keeping a close eye on tax policy to align and update planning where necessary. Josh believes building long-term relationships is essential to effectively managing the tax and compliance of families, their trusts, estates, and succession plans.

Josh lives in the Kent countryside with his wife and has recently become a father, which the dogs and cats are still coming to terms with.

David Crabtree

Partner

David has been advising clients on US and UK international tax issues for over 12 years. David is a dual US (EA) and UK (CTA) qualified tax advisor and established himself as a senior figure at a then leading US/UK tax practice prior to transferring into the Big 4.

David leads the high-net-worth US/UK practice which is well suited to his background working with US connected individuals across different industries. David also specialises in working with private equity and finance executives along with entrepreneurs where he has an extensive background in helping them navigate through their cross jurisdictional issues.

David is committed to truly getting to know his clients and is known throughout his career for developing long lasting relationships as a trusted tax advisor.  David works with his clients to consider long-term views and planning opportunities by breaking down complex issues into more understandable solutions.

David places a strong focus on building a high performing team to ensure clients receive a high-quality service from all aspects of their OSCO experience.

In his spare time David enjoys travelling around the world experiencing different cultures as well as having a keen interest in sports especially football, cricket, rugby and skiing.

Jillian Symes

Partner

Educated in the US and licensed to practice law in both Missouri and Kansas, Jillian has been providing US international corporate tax advice in London for over 17 years. She has extensive experience advising on corporate and international US tax matters, with a focus on private clients with a US connection.

Jillian began her career in London at a Big 4 firm which gave her the opportunity to work with a wide variety of private clients, including entrepreneurial businesses and their owners, family offices with a US connection and HNW/UHNW individuals. Jillian’s goal is to help clients navigate the complex world of US tax in a practical and accessible way to manage risk whilst remaining commercial.

Jillian has helped numerous UK and European businesses expand into the US market – from setting up their structure to annual US corporate compliance. She has extensive experience with internal and third party M&A advice, helping business owners restructure for commercial and M&A activity, including advising US managers.

In addition, Jillian has advised clients with respect to US CFC, PFIC, W-8 reporting and other international and corporate US tax matters.

Away from the office, Jillian is delighted that her daughter has inherited her love of musical theatre and she enjoys attending West End shows with her husband and daughter. 

Louise Palmer

Partner

Louise is a Partner in the Trust, Estates and Family practice, working alongside Josh to co-lead the team. With nearly 15 years of experience, Louise has developed a specialism in the US taxation of foreign trusts. She advises trustees, settlors, and beneficiaries on cross-border tax exposure, filing obligations, and strategic succession planning opportunities.

Her work is grounded in building strong relationships with like-minded advisors and trustees—an essential element in the private client space. Louise has a particular focus on clients with US connections, guiding international families through complex tax strategies while staying closely attuned to the ever evolving tax rules.

Louise is passionate about delivering clear, effective, and manageable tax solutions. Her dedication to the field was previously recognised with the Top 35 Under 35 e-private client award.

Outside of work, she enjoys ticking off destinations on her travel bucket list, dining out, and spending time with her two young children.

Alfredo Ammendola

Director

Alfredo began his US tax career at a Big4 in New York City more than 17 years ago. During this time, he assisted a diverse range of clients—from multinational corporations to real estate funds—with their US tax reporting and advisory needs.

Since 2013, apart from a two-year rotation back in the US, Alfredo has been based in London, focusing on clients in the wealth and asset management industry. He primarily works with private equity and real estate fund managers, helping them navigate US tax issues and reporting requirements arising from having US investors or investments.

Alfredo takes pride in finding reliable, practical solutions, and guiding clients through complex US tax concepts, making the reporting process as straightforward and efficient as possible while ensuring compliance.

Outside of work, Alfredo enjoys spending time with his family and heading to the coast whenever he can.

Ahmed Cassim

Director

Ahmed has spent his entire professional career focusing on private client tax matters for internationally connected US and UK individuals. Being qualified in both the US and UK, Ahmed can handle the varied and complex cross-jurisdictional needs of his clients and their associated advisors.

Whilst Ahmed works with all types of clients – trustees, grantors, beneficiaries, and their family structures are his forte. Ahmed believes long-term planning is key, as the families he looks after are not just spread across different geographical locations but are also in different stages of their lives and careers. He therefore focuses on the needs of each individual within an engagement to ensure all aspects of their tax and planning are covered in the context of the overall picture.

Ahmed is a director in the trust, estates, and family practice, working closely with Josh to ensure a first-rate offering. Ahmed is very methodical in his approach, which ensures there are no gaps in his planning and compliance and has a unique way of communicating niche international tax issues to his clients in a simplified manner. To this effect, Ahmed enjoys guiding his clients through complex tax matters in a clear and understandable way and believes that ongoing communication is key to providing a quality service.

Beyond the office walls, Ahmed can usually be found exploring London’s gig and theatre venues or sampling the new (and his regular) restaurant offerings

Michael Sinclair

Director

Michael has a wealth of experience providing tax and financial advice to individuals, entrepreneurs, and their businesses. He takes a commercially driven approach to advising clients, considering the full spectrum of personal and corporate tax issues, as well as the implications on their short-, medium- and long-term goals.

During their growth journey he advises on areas such as debt/equity fundraises, implementing share incentive schemes, expanding business operations to/from the UK, and cash extraction.

When clients reach the point of exit, he guides them through business disposals, covering pre-transaction planning, post-sale structuring, residency considerations, and wider M&A tax issues. For those retaining their companies, he regularly advises on inheritance tax exposure, shareholder planning, corporate reorganisations, and the establishment of family investment companies.

Most of his spare time is spent playing or watching sport, since hanging up his rugby boots, he socially plays padel, football, tennis, and squash.

Anthony Taylor

Senior Manager

Anthony is a dual US/UK qualified tax advisor and has been working in private client tax since 2016. Anthony initially began his career on the graduate scheme at the then market leading US/UK tax practice, before transferring into Big 4.

Anthony specialises in assisting entrepreneurs and large stakeholders in navigating the intricacies of owning non-US companies whilst being a US citizen or tax resident. Anthony provides effective tax planning strategies to ensure the alignment of income and tax categorisation across all relevant jurisdictions to minimise his clients’ global tax exposure. Anthony’s client base ranges from individuals owning single-member entities to those with shareholdings in large multinational structures.

Anthony leads the compliance offering for the privately owned business group and believes in developing strong client relationships. The strong relationships give Anthony a contextual understanding of his clients’ corporate and individual tax world to ensure his approach is aligned with their overall tax strategy as well as that of their business. Tax compliance for business owners is complex and can be onerous, Anthony’s efficient approach makes the compliance for his clients as seamless as possible.

Outside of work, Anthony enjoys a wide range of sports and can usually be found either on the sidelines managing his local football club, Chalfont Wasps FC, or in the stands at London Stadium watching West Ham.

Adam Lamb

Senior Manager

Adam is a dual-qualified US and UK tax adviser specialising in helping individuals manage complex cross-border tax matters. He began his career in 2016 on an apprenticeship scheme at a Big Four accounting firm, where he gained invaluable experience working with clients navigating international tax complexities.

Since then, Adam has focused on assisting US citizens living in the UK, UK residents moving to the US, and US-connected clients based in other jurisdictions. With extensive experience in the interplay between US and UK tax systems, he provides tailored advice to ensure compliance with ever-changing tax laws and reporting requirements. Adam works closely with clients to minimise risks associated with non-compliance, from managing dual filing obligations to resolving potential conflicts between the differing tax regimes. His expertise ensures that clients meet their tax obligations while maintaining financial efficiency.

Adam simplifies the intricate tax issues that come with a global lifestyle, delivering clear and actionable strategies aligned with his clients’ financial goals. His expertise and commitment make him a trusted adviser for individuals seeking clarity, confidence, and peace of mind in an increasingly globalised financial environment.

Outside of the office, Adam can be found at Roots Hall watching Southend United, out for a run around the streets of South East London or getting a round of golf in with friends

Paul Cadman

Senior Manager

Paul is an experienced private client US/UK Tax Advisor who began his career in tax in 2017 as a graduate at a leading boutique London-based US/UK tax firm.

Paul’s expertise spans a diverse client base, including business owners, senior company executives, hedge fund professionals, and angel investors. His work frequently involves navigating the intricacies of cross-border taxation, with experience coordinating with tax professionals across the globe.

Specialising in high-net-worth individuals, Paul provides comprehensive support in both tax compliance and sophisticated advisory matters. He has extensive experience assisting clients with delinquent US and UK tax filings, multi-year submissions, voluntary and non-voluntary disclosure programs, and collaborating with legal professionals. Additionally, Paul advises on the US tax implications of expatriation, including the process of relinquishing US citizenship.

In his free time, Paul likes to support his favourite rugby team, Northampton Saints, and he regularly attends his local football team with his friends.

Felipe Toledo

Senior Manager

Felipe is a US corporate international tax advisor who has extensive experience in the M&A space. He holds an LL.M. in International Taxation from New York University School of Law and is enrolled to practice before the Internal Revenue Service.

Felipe spent several years at a Big 4 firm in New York and London, focusing on M&A and cross-border transactions. His experience includes leading US tax due diligence engagements for corporate and private equity clients, advising on structuring matters involving C corporations and S corporations, and supporting complex inbound investments. He has worked extensively on matters involving Section 7874 inversions, PFICs, FIRPTA, withholding taxes, GILTI, Subpart F income, permanent establishment and treaty analysis.

More recently, Felipe has advised private equity and venture capital funds on US tax compliance, supporting both fund sponsors and portfolio companies on a range of partnership and corporate tax issues.

Outside of work, Felipe enjoys cycling and exploring the UK’s medieval towns to fuel his passion for history.

Alex Simpson

Director

Alex has spent his professional career advising UK‑resident and internationally mobile individuals on the increasingly complex tax landscape. His practice centres on UK taxation for clients with cross‑border interests, helping them navigate multi‑jurisdictional issues with clarity and confidence.

CTA‑qualified and a STEP Affiliate, Alex is recognised for his technical depth and pragmatic approach. He has been named in the eprivateclient Top 35 Under 35, reflecting his reputation as a trusted adviser to entrepreneurs, senior executives, family offices, trustees and globally mobile families.

Leading the UK Private Client team, Alex heads a dynamic practice delivering strategic, forward‑looking tax advice based on building strong and long-lasting relationships with their clients.

His team supports domestic and international clients with a full suite of services, including inbound and outbound UK tax and residence planning, structuring international assets efficiently, managing cross-border tax issues, inheritance tax planning and handling HMRC enquiries and disclosures.  He believes a proactive approach to compliance is a cornerstone of the service offering, both to identify planning opportunities as well as to implement.

Known for his clear communication and strategic insight, Alex works closely with clients to optimise their tax position while ensuring robust compliance in an environment of increasing scrutiny from tax authorities worldwide.

Away from work, Alex likes to travel when he can with his partner and children.

Eric Collins

Partner

Eric has more than 20 years of experience advising businesses, funds, partnerships and business owners on complex US tax matters. Originally from Newcastle, he moved to the US over 15 years ago and is now based in New York.

He specialises in corporate tax compliance and advisory services, with a particular focus on helping international businesses establish and expand their operations in the US. Eric works with privately owned businesses, investment vehicles and multinational groups, helping clients navigate the complexities of the US tax system while balancing compliance requirements with commercial objectives.

Known for his practical and accessible approach, Eric provides clear, commercially focused advice that helps clients manage tax risk and meet their reporting obligations in an increasingly global environment.

Outside of work, Eric enjoys spending time with his wife and two children and is a keen snowboarder who enjoys the outdoors.

Mark Perry

Director

Mark is a veteran Employer Solutions specialist with over 20 years of experience. As a former HMRC Inspector who personally concluded over 500 enquiries and reviews from the inside, Mark brings an unmatched level of technical authority to the firm.  He pairs this deep regulatory insight with a highly practical, problem-solving mindset, helping businesses shield themselves from costly disputes and proactively manage risk.

Mark provides proactive, real-time advice on employment tax matters, helping clients navigate HMRC enquiries, CIS, payroll, IR35 and National Minimum Wage compliance. He also advises on global mobility and cross-border employment tax matters.

Mark’s experience spans P11Ds, PAYE Settlement Agreements, Employment Related Securities, and employment tax support on corporate transactions. He also works closely with cross-border private clients and growing businesses to address time-sensitive international equity matters, including share option planning, equity incentives, the Foreign Income and Gains (FIG) regime and Overseas Workday Relief (OWR).

Outside of work Mark has recently taken on an allotment and is a keen Norwich City supporter with an acute dislike of VAR and hydration breaks!

Stuart Daltrey

Partner

Stuart is an Employer Solutions Partner at Ostberg Sinclair & Co, bringing more than 25 years of specialist experience across the full spectrum of employment tax, payroll and global mobility matters.

As a Chartered Tax Adviser, Stuart combines exceptional technical expertise with a personable, relationship-focused approach. He takes the time to understand each client’s unique challenges and objectives, delivering tailored solutions that build lasting trust and establish him as a trusted adviser in this complex area.

Stuart believes in a lifecycle-led approach to client relationships, building on the principles of trusted advisory. He works alongside businesses at every stage of their journey, providing seamless support from start-up and growth through to international expansion and eventual exit.

Outside of work, Stuart enjoys a wide range of sports, playing and watching, he currently coaches the reserve team at Step 2 club Billericay and when he can goes over to watch his team West Ham.