ArborText
- Developer of SGML authoring and publishing tools.
- http://www.ptc.com/company/arbortext/

Mulberry Technologies, Inc.
- Provide SGML services include consulting, training, and design.
- http://www.mulberrytech.com/services/index-sgml.html

Alden Group Ltd: Typesetting and Printing Academic Journals and Publications
- Typesetters and manufacturers of academic books and journals, translation service, software development and web development, SGML, pdf, DTD and XML conversion and creation. Technical consultancy and seminars
- http://www.alden.co.uk

Architag
- Content management and data structuring company using SGML and applied formats.
- http://architag.com/

SPI Technologies Inc.
- data conversion services, specializing in SGML/HTML/XML structuring, automated mapping/facilities management conversions, litigation support, and pre-press
- http://www.spitech.com

Incremental Development, Inc.
- SGML and XML consulting - eight years experience. We help structure text and surrounding business processes with emphasis on simplicity and skill transfer.
- http://incrementaldevelopment.com/