Financial capital, or economic capital, is any liquid medium or mechanism that represents wealth, i.e. other styles of capital. A contract regarding any combination of capital asset is called a financial instrument, and may serve as a Liquidity requirements of these vary significantly - leading to a diversity of contracts and financial markets to trade them on. When all four functions are served by one instrument, this is called money, which does not need to be traded on financial markets since the risk of loss of value of money is uniform across the whole society. Where no one form of money is agreed to have reliable value, and barter is undesirable, less liquid or more diverse instruments have served the four functions. This article focuses mostly on financial instruments which are not uniformly affected by native currency inflation and which are not guaranteed by a state.

Like money, financial instruments may be "backed" by state military fiat, credit (i.e. social capital held by banks and their depositors), or commodity resources. Governments generally closely control the supply of it and usually require some "reserve" be held by institutions granting credit. Trading between various national currency instruments is conducted on a money market. Such trading reveals differences in probability of debt collection or store of value function of that currency, as assigned by traders.

When in forms other than money, financial capital may be traded on bond markets or reinsurance markets with varying degrees of trust in the social capital (not just credits) of bond-issuers, insurers, and others who issue and trade in financial instruments. When payment is deferred on any such instrument, typically an interest rate is higher than the standard interest rates paid by banks, or charged by the central bank on its money. Often such instruments are called fixed-income instruments if they have reliable payment schedules associated with the uniform rate of interest. A variable-rate instrument, such as many consumer mortgages, will reflect the standard rate for deferred payment set by the central bank prime rate, increasing it by some fixed percentage. Other instruments, such as citizen entitlements, e.g. "U.S. Social Security", or other pensions, may be indexed to the rate of inflation, to provide a reliable value stream.

Trading in stock markets or commodity markets is actually trade in underlying assets which are not wholly financial in themselves, although they often move up and down in value in direct response to the trading in more purely financial derivatives. Typically commodity markets depend on politics that affect international trade, e.g. boycotts and embargoes, or factors that influence natural capital, e.g. weather that affects food crops. Meanwhile, stock markets are more influenced by trust in corporate leaders, i.e. individual capital, by consumers, i.e. social capital or "brand capital" (in some analyses), and internal organizational efficiency, i.e. instructional capital and infrastructural capital. Some enterprises issue instruments to specifically track one limited division or brand. "Financial futures", "Short-selling" and "financial options" apply to these markets, and are typically pure financial bets on outcomes, rather than being a direct representation of any underlying asset.

The relationship between financial capital, money, and all other styles of capital, especially human capital or labor, is assumed in central bank policy and regulations regarding instruments as above.

Such relationships and policies are characterized by a political economy - feudalist, socialist, capitalist, green, anarchist or otherwise. In effect, the means of money supply and other regulations on financial capital represent the economic sense of the value system of the society itself, as they determine the allocation of labor in that society.

So, for instance, rules for increasing or reducing the money supply based on perceived inflation, or on measuring well-being, reflect some such values, reflect the importance of using (all forms of) financial capital as a stable store of value. If this is very important, inflation control is key - any amount of money inflation reduces the value of financial capital with respect to all other types.

If, however, the medium of exchange function is more critical, new money may be more freely issued regardless of impact on either inflation or well-being.

Unit of account functions may come into question if valuations of complex financial instruments vary drastically based on timing. The "book value", "mark-to-market" and "mark-to-future" conventions are three different approaches to reconciling financial capital value units of account.

Socialism, capitalism, feudalism, anarchism, other civic theories take markedly different views of the role of financial capital in social life, and propose various political restrictions to deal with that.

See also