Asklemmy

So in the US, there are two kinds of corporations: Public (as in publicly traded on the stock market) and Privately owned (shareholders with stock unavailable to the public).

Publicly traded companies are required to be much more transparent to the public and their potential/active investors (to deter earnings fraud ala Enron), so therefore have plenty of data published for analysts to work with.

Privately held companies, by contrast, don't need to tell the public anything. By not being listed on the stock market, they can do almost anything they'd like with little danger of their business practices being scrutinized (It also doesn't help that the US is relatively weak when it comes to business regulation to begin with).

However, one advantage of this is that they aren't beholden to public investors demanding growth above all else - Publicly traded companies are legally bound to prioritize shareholder demands ahead of any other duties. Valve, for example, is able to perform a lot more pro-consumer moves with their services and software because they don't have Wall Street hounding them for quarterly returns.

Unfortunately, the reality is you can't have the best of both situations from the public's perspective. The US has more financial obscurity than is typically presented, and that often manifests as businesses dodging regulation, oversight, and accountability as much as possible. Mars, for instance, probably has skeletons in their closet on the supply chain front (abuse in the production of chocolate), that may give them incentives to remain as private as possible - no financial records, no transparency reports, no investor conferences.

(Also slightly away from the subject but consolidation is incredibly high in the US - many industries are effectively controlled by an oligopoly of companies)