Helpfully, the US Government, specifically the SEC, defines the term “public company” for us: “There are two commonly understood ways in which a company is con

Helpfully, the US Government, specifically the SEC, defines the term “public company” for us: “There are two commonly understood ways in which a company is considered public: first, the company’s securities trade on public markets; and second, the company discloses certain business and financial information regularly to the public. In general, we use the term to refer to a company that has public reporting obligations.” They’re talking about $TWTR, not Amtrak.