Non-banking financial companies (NBFCs), especially housing finance companies (HFCs), are likely to witness a slowdown in the appetite for their bonds as a result of the recent revision of investment norms for debt-oriented mutual fund managers, according to a research report by credit agency India Ratings. The present portfolio composition indicates that the overall sector exposure for NBFCs and HFCs stands at around 30%, and is broadly in line with the revised norms. So, an incremental appetite is likely to be tepid.