One problem with all the approaches is a lack of consistency in the industry taxonomies. And even when you have a formal taxonomy like SIC or NAICS, the lack of consistency in how the values are assigned. I find that you end up doing some mappings and guess work to put companies into the right industry buckets, for your specific organization’s taxonomy. The need for this mapping argues for my first approach, where you are doing the mapping / guessing in a Clay table, then once you’ve made a decision, you push the mapping out to your master data system via Zapier or some similar middleware routing.