Title: Business sector
Content:  In economics, the business sector or corporate sector - sometimes popularly called simply "business" - is "the part of the economy made up by companies". It is a subset of the domestic economy, excluding the economic activities of general government, of private households, and of non-profit organizations serving individuals. The business sector is part of the private sector, but it differs in that the private sector includes all non-government activity, including non-profit organizations, while the business sector only includes business that operate for profit. In the United States the business sector accounted for about 78 percent of the value of 
Title: Public sector
Content:  The public sector (also called the state sector) is the part of the economy composed of both public services and public enterprises. Public sectors include public goods and governmental services such as the military, law enforcement, infrastructure, public transit, public education, along with health care and those working for the government itself, such as elected officials. The public sector might provide services that a non-payer cannot be excluded from (such as street lighting), services which benefit all of society rather than just the individual who uses the service. Public enterprises, or state-owned enterprises, are self-financing commercial enterprises that are under public ownership which provide various private goods and services for sale and usually operate on a commercial basis. Organizations that are not part of the public sector are either part of the private sector or voluntary sector. The private sector is composed of the economic sectors that are intended to earn a profit for the owners of the enterprise. The voluntary, civic or social sector concerns a diverse array of non-profit organizations emphasizing civil society.
Title: Economic sector
Content: Public sector or state sector ; Private sector or privately run businesses ; Voluntary sector An economy can also be divided along different lines: 
Title: Private sector
Content:  The private sector is the part of the economy, sometimes referred to as the citizen sector, which is owned by private groups, usually as a means of establishment for profit or non profit, rather than being owned by the government.
Title: Public company
Content:   A public company, publicly traded company, publicly held company, publicly listed company, or public limited company is a company whose ownership is organized via shares of stock which are intended to be freely traded on a stock exchange or in over-the-counter markets. A public company can be listed on a stock exchange (listed company), which facilitates the trade of shares, or not (unlisted public company). In some jurisdictions, public companies over a certain size must be listed on an exchange. In most cases, public companies are private enterprises in the private sector, and "public" emphasizes their reporting and trading on the public markets. Public companies 
Title: Economy
Content:  undamaged portions of it can be made into pulp for paper.) Note that education is sometimes included in this sector. the public sector or state sector (which usually includes: parliament, law-courts and government centers, various emergency services, public health, shelters for impoverished and threatened people, transport facilities, air/sea ports, post-natal care, hospitals, schools, libraries, museums, preserved historical buildings, parks/gardens, nature-reserves, some universities, national sports grounds/stadiums, national arts/concert-halls or theaters and centers for various religions). ; the private sector or privately run businesses. ; the social sector or voluntary sector. The economy may be considered as having developed through the following phases or degrees of precedence. In modern economies, these phase precedences are somewhat differently expressed by the three-sector theory. Other sectors of the developed community include : 
Title: Platform economy
Content:  Most of the widely used platforms are owned by the private sector. In the 2016 GCE survey of platform companies valued over $1 billion, a total of 107 privately owned companies were found, versus 69 public companies (public in the sense of being private sector, but publicly traded ). While more numerous, the privately owned companies tended to be smaller, having a total market value of $300 billion, compared to $3,900 billion for the publicly traded companies.
Title: Japanese public corporations
Content:  Although the Japanese economy is largely based on private enterprise, it has a number of government-owned (public) corporations, which are more extensive and, in some cases, different in function from what exists in the United States.
Title: Privately held company
Content:  A privately held company or private company is a company which does not offer or trade its company stock (shares) to the general public on the stock market exchanges, but rather the company's stock is offered, owned and traded or exchanged privately or over-the-counter. In the case of a close corporation, there are a relatively small number of shareholders or company members. Related terms are closely held corporation, unquoted company, and unlisted company. Though less visible than their publicly traded counterparts, private companies have major importance in the world's economy. In 2008, the 441 largest private companies in the United States accounted for US$1.8 trillion ($1.8 trillion) in revenues and employed 6.2 million people, according to Forbes. In 2005, using a substantially smaller pool size (22.7%) for comparison, the 339 companies on Forbes survey of closely held U.S. businesses sold a trillion dollars' worth of goods and services (44%) and employed four million people. In 2004, the Forbes count of privately held U.S. businesses with at least $1 billion in revenue was 305. Separately, all non-government-owned companies are considered private enterprise. This sense includes both publicly-traded and privately-held companies, as their investors are individuals in the private sector.
Title: Public finance
Content:  (See Figure 1). The concept of general government does not include public corporations. The general government plus the public corporations comprise the public sector (See Figure 2).   The general government sector of a nation includes all non-private sector institutions, organisations and activities. The general government sector, by convention, includes all the public corporations that are not able to cover at least 50% of their costs by sales, and, therefore, are considered non-market producers. In the European System of Accounts, the sector “general government” has been defined as containing: Therefore, the main functions of general government units are : The general government sector, in the European System of Accounts, has four sub-sectors:  "Central 

Question: public companies are part of what economic sector?
Answer: public sector.
The public sector.