Exchange rates for such currencies are likely to change almost constantly

The raising of capital (in the capital markets);
The transfer of risk (in the derivatives markets);
International trade (in the currency markets)
– and are used to match those who want capital to those who have it.
Typically a borrower issues a receipt to the lender promising to pay back the capital. These receipts are securities which may be freely bought or sold. In return for lending money to the borrower, the lender will expect some compensation in the form of interest or dividends.
In mathematical finance, the concept of a financial market is defined in terms of a continuous-time Brownian motion stochastic process.
In economics, a financial market is a mechanism that allows people to easily buy and sell (trade) financial securities (such as stocks and bonds), commodities (such as precious metals or agricultural goods), and other fungible items of value at low transaction costs and at prices that reflect the efficient-market hypothesis.
Financial markets have evolved significantly over several hundred years and are undergoing constant innovation to improve liquidity.
Both general markets (where many commodities are traded) and specialized markets (where only one commodity is traded) exist. Markets work by placing many interested buyers and sellers in one "place", thus making it easier for them to find each other. An economy which relies primarily on interactions between buyers and sellers to allocate resources is known as a market economy in contrast either to a command economy or to a non-market economy such as a gift economy.
If a currency is free-floating, its exchange rate is allowed to vary against that of other currencies and is determined by the market forces of supply and demand. Exchange rates for such currencies are likely to change almost constantly as quoted on financi market.
Market convention from the early 1980s to 2006 was that most currency pairs were quoted to 4 decimal places for spot transactions and up to 6 decimal places for forward outrights or swaps. (The fourth decimal place is usually referred to as a "pip"). An exception to this was exchange rates with a value of less than 1.000 which were usually quoted to 5 or 6 decimal places. Although there is no fixed rule, exchange rates with a value greater than around 20 were usually quoted to 3 decimal places and currencies with a value greater than 80 were quoted to 2 decimal places. Currencies over 5000 were usually quoted with no decimal places (e.g. the former Turkish Lira). e.g. (GBPOMR : 0.765432 - EURUSD : 1.5877 - GBPBEF : 58.234 - EURJPY : 165.29).

Borrowers would have difficulty finding lenders themselves

Many individuals are not aware that they are lenders, but almost everybody does lend money in many ways. A person lends money when he or she:
puts money in a savings account at a bank;
contributes to a pension plan;
pays premiums to an insurance company;
invests in government bonds; or
invests in company shares.
More complex transactions than a simple bank deposit require markets where lenders and their agents can meet borrowers and their agents, and where existing borrowing or lending commitments can be sold on to other parties. A good example of a financial market is a stock exchange. A company can raise money by selling shares to investors and its existing shares can be bought or sold.
The following table illustrates where financial markets fit in the relationship between lenders and borrowers
To understand financial markets, let us look at what they are used for, i.e. what is their purpose?
Without financial markets, borrowers would have difficulty finding lenders themselves. Intermediaries such as banks help in this process. Banks take deposits from those who have money to save. They can then lend money from this pool of deposited money to those who seek to borrow. Banks popularly lend money in the form of loans and mortgages.
In economics, typically, the term market means the aggregate of possible buyers and sellers of a thing and the transactions between them.
The term "market" is sometimes used for what are more strictly exchanges, organizations that facilitate the trade in financial securities, e.g., a stock exchange or commodity exchange. This may be a physical location (like the NYSE) or an electronic system (like NASDAQ). Much trading of stocks takes place on an exchange; still, corporate actions (merger, spinoff) are outside an exchange, while any two companies or people, for whatever reason, may agree to sell stock from the one to the other without using an exchange.
Trading of currencies and bonds is largely on a bilateral basis, although some bonds trade on a stock exchange, and people are building electronic systems for these as well, similar to stock exchanges.
Financial markets can be domestic or they can be international.

English joint stock company established by royal charter by James

Companies law (or the law of business associations) is the field of law concerning companies and other business organizations. It is an establishment formed to carry on commercial enterprises.[1] This includes corporations, partnerships and other associations which usually carry on some form of economic or charitable activity. The most prominent kind of company, usually referred to as a "corporation", is a "juristic person", i.e. it has separate legal personality, and those who invest money into the business have limited liability for any losses the company makes, governed by corporate law. The largest companies are usually publicly listed on stock exchanges around the world. Even single individuals, also known as sole traders may incorporate themselves and limit their liability in order to carry on a business.
According to one source, "it may be formed by Act of Parliament, by Royal Charter, or by registration under company law (referred to as a limited liability or joint-stock company)."In the United Kingdom, the main regulating laws are the Companies Act 1985 and the Companies Act 2006.[3] Reportedly, "a company registered under this Act has limited liability: its owners (the shareholders) have no financial liability in the event of winding up the affairs of the company, but they might lose the money already invested in it",In the USA, companies are registered in a particular state—Delaware being especially favoured—and become Incorporated (Inc).
In North America, two of the earliest companies were The London Company (also called the Charter of the Virginia Company of London)—a English joint stock company established by royal charter by James I of England on April 10, 1606 with the purpose of establishing colonial settlements in North America—and Plymouth Company that was granted an identical charter as part of the Virginia Company. The London Company was responsible for establishing the Jamestown Settlement, the first permanent English settlement in the present United States in 1607, and in the process of sending additional supplies, inadvertently settled the Somers Isles, alias Bermuda, the oldest-remaining English colony, in 1609.

The most common form of company used for business ventures

A company limited by guarantee. Commonly used where companies are formed for non-commercial purposes, such as clubs or charities. The members guarantee the payment of certain (usually nominal) amounts if the company goes into insolvent liquidation, but otherwise they have no economic rights in relation to the company .
a company limited by guarantee with a share capital. A hybrid entity, usually used where the company is formed for non-commercial purposes, but the activities of the company are partly funded by investors who expect a return.
a company limited by shares. The most common form of company used for business ventures.
an unlimited liability company. A company where the liability of members for the debts of the company are unlimited. Today these are only seen in rare and unusual circumstances.
There are, however, many specific categories of corporations and other business organizations which may be formed in various countries and jurisdictions throughout the world.

Businesses that follow certain guidelines

As theorists such as Ronald Coase have pointed out, all business organizations represent an attempt to avoid certain costs associated with doing business. Each is meant to facilitate the contribution of specific resources - investment capital, knowledge, relationships, and so forth - towards a venture which will prove profitable to all contributors. Except for the partnership, all business forms are designed to provide limited liability to both members of the organization and external investors. Business organizations originated with agency law, which permits an agent to act on behalf of a principal, in exchange for the principal assuming equal liability for the wrongful acts committed by the agent. For this reason, all partners in a typical general partnership may be held liable for the wrongs committed by one partner. Those forms that provide limited liability are able to do so because the state provides a mechanism by which businesses that follow certain guidelines will be able to escape the full liability imposed under agency law. The state provides these forms because it has an interest in the strength of the companies that provide jobs and services therein, but also has an interest in monitoring and regulating their behaviour.

Ownership interests in large corporations

Law schools typically offer either a single upper level course on business organizations, or offer several courses covering different aspects of this area of law. The area of study examines issues such as how each major form of business entity may be formed, operated, and dissolved; the degree to which limited liability protects investors; the extent to which a business can be held liable for the acts of an agent of the business; the relative advantages and disadvantages of different types of business organizations, and the structures established by governments to monitor the buying and selling of ownership interests in large corporations.
The basic theory behind all business organizations is that, by combining certain functions within a single entity, a business (usually called a firm by economists) can operate more efficiently, and thereby realize a greater profit. Governments seek to facilitate investment in profitable operations by creating rules that protect investors in a business from being held personally liable for debts incurred by that business, either through mismanagement, or because of wrongful acts.