SEC has the Edgar database where you can lookup any company and access there different SEC forms, but you still need to know which forms to look for the information in. For example, the 10k of one company had the ownership informing of top shareholders, but I wasn’t able to find that info in the 10k of another company (possibly because I didn’t know where to look). I know you can use EDGAR database to at least lookup these forms, but I do not know the full capabilities of the database (such as if you can query for ownership directly) because I just discovered it the other day.