Where does haram income data come from?

There are several data providers that research stocks and calculate impure and questionable income. Each provider comes up with different numbers, so classifying stocks as halal is not always the same. Does anyone know where Zoya gets it’s impure revenue data or if they are calculating it in-house (which would be a massive undertaking for a small company)?

We’ve built proprietary tech that allows us to do it all in house and without having to rely on analysts. The underlying raw data is sourced from several different financial data providers (in some cases, we’ll pull directly from the respective company’s investor relations site) and then put through our screener to be evaluated for shariah compliance. Each revenue segment reported by a company is evaluated individually and then we tally up the total percentages.

Jazakallahu khairan for the detailed response.