Terminological resources offer potential to support applications beyond translation, such as controlled authoring and indexing, which are increasingly of interest to commercial enterprises. The ad-hoc semasiological approach adopted by commercial terminographers diverges considerably from methodologies prescribed by conventional theory. The notion of termhood in such production-oriented environments is driven by pragmatic criteria such as frequency and repurposability of the terminological unit. A high degree of correspondence between the commercial corpus and the termbase is desired. Research carried out at the City University of Hong Kong using four IT companies as case studies revealed a large gap between corpora and termbases. Problems in selecting terms and in encoding them properly in termbases account for a significant portion of this gap. A rigorous corpus-based approach to term selection would significantly reduce this gap and improve the effectiveness of commercial termbases. In particular, single-word terms (keywords) identified by comparison to a reference corpus offer great potential for identifying important multi-word terms in this context. We conclude that terminography for production purposes should be more corpus-based than is currently the norm.