Short answers, pulled from the story.
A privately held company is one whose shares are not offered for public subscription or traded on listed markets; ownership is transferred privately, also known as over-the-counter. Public companies, by contrast, list their shares on stock exchanges where the general public can buy and sell them.
In 2008, the 441 largest private companies in the United States generated $1.8 trillion in revenues and employed 6.2 million people, according to Forbes. That figure covers only the largest privately held firms, not the full universe of small businesses, most of which are also privately held.
In the United States, privately held companies are not generally required to publish their financial statements. This contrasts with public companies, which must file detailed disclosures with regulators.
Section 12(g) of the U.S. Securities Exchange Act of 1934 generally limits a privately held company to fewer than 2,000 shareholders. The U.S. Investment Company Act of 1940 also requires registration of investment companies with more than 100 holders.
In the United Kingdom, a close or closely held company is defined as a company controlled by either five or fewer shareholders, or by shareholders who are also directors.
Indian private companies must include the words Private Limited at the end of their names. They are registered by the Registrar of Companies, which operates under the Ministry of Corporate Affairs.