Letters & Thoo

IAM Research

The Patent 1000 focuses exclusively on patent practice and has firmly established itself as the definitive 'go-to' resource for those seeking world-class legal patent expertise.

Highly-recommended - Firms: prosecution

Letters & Thoo is one of the city’s foremost prosecution shops. Whether prosecuting Hong Kong or European patent applications for its illustrious array of service users, the outfit has unquestionable technical acumen and achieves the highest standard of drafting. With his PhD in biomedical engineering, the eponymous Timothy Letters is a prolific drafter and prosecutor of medical and life sciences space. Alongside him is fellow namesake partner Laurence Thoo, who is an outstanding troubleshooter when it comes to technically challenging electronics, telecommunications and computer hardware and software matters.

Firm Profile

Letters & Thoo is a specialist IP practice based in Hong Kong, with internationally recognised expertise in the procurement, management and protection of patent, trademark and industrial design rights on behalf of both domestic and international clients.

The firm’s patent attorneys have established a proud and longstanding track record of excellence in the IP field, having been consistently recognised in peer review industry benchmark publications, including the IAM Patent 1000 since 2012.

Throughout the years, clients have come to know us not only for the uncompromising quality of our professional services, but also for our commitment to providing accessible and responsive client care at all times.

Letters & Thoo constantly strives to maintain these high standards by providing client-focused IP services to clients of all sizes and from all sectors.

Patent services

Letters & Thoo assists clients in all aspects of substantive patent prosecution and practice, including patent filing services in Hong Kong, China and internationally, patent drafting, patent validity and infringement analysis, freedom-to-operate opinions and exploitation of patent rights, as well as the management of patent portfolios.

Letters & Thoo’s attorneys handle a diverse range of technologies, including mechanical and electro-mechanical devices and systems, materials sciences, manufacturing technologies, analogue and digital electronics, consumer electronics and consumer products, telecommunications and data processing systems, computer hardware and software, e-commerce business systems, and pharmaceutical and chemistry-based technologies.

Today, international companies face uncertainty in assessing their freedom to operate in relation to commercial activities in Hong Kong, China and Southeast Asia. The firm has extensive experience advising clients on such multi-jurisdictional patent clearance matters, including those pertaining to commercial use of non-traditional pharmaceutical and agrochemical technologies.

Trademark and industrial design services

Letters & Thoo provides trademark and industrial design rights services covering both Hong Kong and China, including:

  • preparation, filing and prosecution of trademark applications;
  • advice on registration and use requirements for trademarks;
  • trademark opposition proceedings;
  • cancellation actions against bad-faith trademark registrations in China and Hong Kong;
  • non-use cancellations against registations in China and Hong Kong;
  • trademark availability searches;
  • trade fair enforcement actions; and
  • commercial transactions involving trademark rights.

Letters & Thoo acts for a diverse range of clients in relation to trademark and design matters, including leading luxury goods designers and manufacturing companies covering jewellery, footwear, garments, aspects of product packaging, toys, industrial components, foodstuffs, beverages and household consumer products, as well as computer-related devices, telecommunications devices, graphics and interfaces.

Specialist IP services

Letters & Thoo also provides a range of specialist IP services for clients, including:

  • pharmaceutical freedom-to-operate patent clearance in Hong Kong and compliance with government and domestic supply requirements;
  • advising on tendering and government procurement in compliance with World Trade Organisation requirements relating to IP and government procurement agreements;
  • trade fair IP rights administrative actions in Hong Kong – with particular expertise in the strategic enforcement of standard-essential patent rights, trademark infringement and anti-counterfeiting actions;
  • commercial cross-border patent filing and prosecution strategies for international corporations with manufacturing operations in China and Hong Kong;
  • bad-faith trademark cancellations and recovery of hijacked IP rights by shadow companies; and
  • commercial transactions involving the assignment and licensing of patent rights and underlying technologies.


The firm’s patent attorneys are technically qualified in diverse science and engineering disciplines and have specialist postgraduate qualifications in IP law and practice and many years’ professional experience securing and enforcing IP rights for a wide range of technology, trademark and industrial design owners in Hong Kong, China and internationally.

Letters & Thoo’s patent attorneys have proudly served on the Council of the Asian Patent Attorneys Association Hong Kong Group and on the group’s Patents and Designs Standing Committees; are members of the International Federation of Intellectual Property Attorneys, the International Trademark Association and the Hong Kong Institute of Trademark Practitioners; and are recognised as fellows of the Institute of Patent and Trademark Attorneys of Australia.

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