The Enneagram has become a substantial industry, and that shapes what is written about it. There are competing schools with their own trademarks, certifications and instruments, chief among them the Enneagram Institute founded by Riso and Hudson, the Narrative Enneagram descended from Helen Palmer and David Daniels, Naranjo's own SAT lineage, and Ichazo's Arica Institute, which has asserted proprietary claims over the material and litigated against other publishers. Corporate training, podcasts, books and paid tests make up a market of some size. The relevance to a reader is practical: descriptions of the types differ between schools, the type names used here are Riso and Hudson's, and confident claims about the system's antiquity are frequently made by parties with an interest in making them.
One institutional response to the proliferation of competing schools came in 1994, when a group of early teachers, including Helen Palmer, David Daniels and Don Riso, founded the International Enneagram Association out of the first International Enneagram Conference held that year at Stanford University, intending a nondenominational professional body that could hold conferences and set shared standards across the rival lineages. It has not resolved the underlying disagreements about type descriptions or about the system's history, since member schools continue teaching their own variants under its umbrella.