Interest (English spelling)

Japanese: 利子 - りし（英語表記）interest 英語

Remuneration for lending funds for a certain period of time. The percentage of interest paid to the principal amount loaned is called the interest rate. Interest is also called interest, and interest rate is also called the interest rate.

[Shiro Hara and Osamu Kitai]

Interest from the Perspective of Modern Economics

Interest and interest rates tend to be seen as monetary because they are established according to the borrowing and lending of funds, but a view that emphasizes the role that interest and interest rates play in resource allocation from a real perspective has long been advocated. For example, Böhm-Bawerk, K. Wicksell, and I. Fischer have taken this position. In other words, interest is a reward for a kind of time preference for households to save for future consumption. Since current consumption is sacrificed, a reward (interest) is paid for this, and the higher this interest rate is, the more households will try to increase their savings level. Also, companies will try to increase future productivity by increasing a certain amount of equipment, even if it means reducing current production. As a result, profits (profits) are obtained, so they will try to pay interest on the funds to increase this equipment. This is called the investment behavior of a company, and companies will earn a certain profit based on their investment behavior. If the rate of profit on investment is higher than the interest rate paid when borrowing funds in the market, companies will invest. The level of savings, based on households' time preferences, and the level of investment by companies are determined by the level of interest rates in the market, where the former is a supply and the latter is a demand. This interest rate can be considered to be the real interest rate.

Another way of looking at interest rates is as monetary interest rates, and a representative explanation is J.M. Keynes's liquidity preference theory. In other words, it claims that interest rates are a reward for people giving up their money, which has the advantage of being liquid, in order to hold financial assets that generate interest, such as bonds. The higher the interest rate, the more people will give up their money in order to hold bonds. Keynes claimed that investment is determined when the monetary interest rate thus established coincides with the marginal efficiency of capital (the expected rate of return for a one-unit increase in capital investment).

The loanable funds theory is one of the theories that determine interest rates. The loanable funds theory asserts that interest rates are determined by the general equilibrium between interest rates in the loanable funds market, which is determined by the supply and demand relationship for funds, and interest rates in the money market, which is determined by the supply and demand relationship for money.

There are two types of interest rates: nominal and real. The real interest rate is the nominal interest rate minus the inflation rate. When the market expects that the inflation rate will rise in the future, the nominal interest rate will rise.

As explained above, interest rates are determined by supply and demand in financial markets, which are divided into a number of markets according to the diversification of financial assets traded there. When classified from the perspective of the maturity of financial assets, they are broadly divided into long-term financial markets (capital markets) and short-term financial markets (money markets), but each market is further subdivided according to the financial assets traded. And because interest rates are established in each market, actual market interest rates are also diverse. There is now a view that there may be a certain regularity among these various interest rates, and this is called the interest rate structure or interest rate system.

There are some ways of looking at the interest rate structure, which look at the relationship between various interest rates according to the degree of marketability and risk of the financial assets being traded, but the most well-known is the term structure of interest rates. This is an attempt to see the relationship between various interest rates as the maturity of financial assets occurs, and a yield curve is used that connects various interest rates, with maturity on the horizontal axis and interest rate on the vertical axis. According to the liquidity preference theory, the yield curve is higher for long-term assets because the period during which liquidity is given up is longer, and therefore the curve slopes upward to the right, but this is not necessarily the case in the expectation theory, which emphasizes future expectations. In other words, when market interest rates are expected to rise in the future, lenders increase their demand for short-term assets, and borrowers increase the supply of long-term assets. As a result, the prices of short-term assets rise and their yields fall, but the prices of long-term assets fall and their yields rise. As a result, the curve slopes upward to the right, with the yields of short-term assets being lower than those of long-term assets, but when the market expects interest rates to fall in the future, the curve slopes downward to the right.

When interest rates are liberalized and left to the market, various types of yield curves can be drawn, but when the government or central bank regulates interest rates, the curve generally slopes upwards. In Japan, almost all interest rates have been regulated since the end of World War II, except for the call rate. In addition, an artificially low interest rate policy has been adopted. As a result, funds have been allocated not by interest rates, but by credit allocation by financial institutions and other institutions. In the 1980s, a series of interest rate liberalization measures were taken, although Japan was behind other developed countries. With the liberalization of interest rates on liquid deposits in October 1994, all deposit interest rates have now been liberalized, except for current deposits (which are prohibited from earning interest). As for lending rates, a new method of determining short-term prime rates was introduced in January 1989, in which each bank determines the lending rate based on the cost of funding and a comprehensive assessment of the financial environment, etc. As for long-term prime rates, a long-term floating lending rate linked to the short-term prime rate was introduced in April 1991, forming a market in which interest rates are determined by the supply and demand relationship in the market.

[Shiro Hara and Osamu Kitai]

Interest from a Marxian perspective

Under capitalist production, in addition to its own definition, money becomes a commodity with a use value called capital, which grows by itself and produces average profits. If the owner of the money transfers this money, which has the ability to produce profits, to another person, the latter becomes a functioning capitalist and pays a portion of the profits produced for the use value of the money that functions as capital. This is called interest. If the money is not transferred, the functioning capitalist cannot produce profits, and the ownership of money does not allow the owner to obtain interest, which is a specific part of profits. Therefore, interest appears as the price of capital, the price of a commodity that has the use value of producing profits through its transfer. And the amount of interest is determined by the interest rate.

[Kaido Katsutoshi]

Interest rates and their fluctuations

The interest rate represents the ratio of interest to loanable money capital. Since interest is a part of the average profit of functioning capitalists, its upper limit is the average profit itself, and its lower limit is infinitely close to zero. Within this limit, the interest rate is determined only by the relationship of demand and supply between borrowers (functioning capitalists) and lenders (monetary capitalists) for loanable capital, and there is no other internal law that determines the interest rate.

The actual movement of the average profit of industrial and commercial capital has nothing to do with fluctuations in the interest rate, except that it places a limit on the fluctuations in the interest rate. In other words, interest rates vary depending on factors affecting the demand and supply of borrowers and lenders, such as the presence or absence, type and grade of collateral, the term of the loan, etc. There are only individual market interest rates that constantly fluctuate in time and place, and there is no natural interest rate to which they will naturally settle. This is because, unlike the individual fluctuations of the profit rate, the demand and supply for loanable capital in the aggregate move simultaneously and on a mass scale, in a uniform form that is indistinguishable from one another, and which is promoted by the development and concentration of the credit industry. Therefore, the interest rate does not have the tendency to average out like the profit rate, but appears clearly as a magnitude that can be directly and fixedly grasped at any moment in daily experience. The average and median rates of interest are only calculated, and are derived in time from averaging the fluctuations of interest rates in the industrial cycle, and in place from calculating the rate at which capital is lent in the long run, since the characteristics of the capital available for lending in the production and distribution processes play no role. The determination of interest rates is purely empirical, subject to the contingencies of supply and demand, custom, and legal tradition.

During recessions, interest rates, along with the rate of profit, are generally extremely low. During booms, they rise gradually due to the enthusiasm of working capital, and during busy periods, they rise due to the speculative expansion of industrial capital. When overproduction occurs, the rate of profit plummets as capital return is lost and the supply of monetary capital decreases, while financing becomes even more strained, causing the interest rate to rise even higher. During depressions, the supply of monetary capital falls sharply, but working capital seeks monetary capital to pay its own debts, and the interest rate soars to its highest level. Thus, the fluctuations in the interest rate are not the same as those in the rate of profit, which determines the state of the industrial cycle.

[Kaido Katsutoshi]

Interest and Corporate Profits

Thus, it is only by the social division of capitalists into money capitalists and functional capitalists that a part of profits becomes interest. The average profit of a functional capitalist who has borrowed is therefore divided quantitatively, first, into the interest he pays to the money capitalists, and the surplus over the interest which is his own share.

Next, a qualitative division between the two begins. The interest paid by the functional capitalist to the money capitalist is considered to be the fruit of his capital ownership, even though the money capitalist is not active in the production and distribution processes, i.e., the part that is the direct product of capital ownership. On the other hand, the surplus of average profits that exceeds the interest attributable to the functional capitalist is considered to be inherent in and arises from his capital function in the production and distribution processes, that is, his active role as an entrepreneur, and appears as the fruit of that. Thus, although they are the same source, they are mutually independent phenomena, as if they arose from two essentially different sources.

Once this division is socially established, even with unborrowed equity capital, a qualitative division of average profits occurs, with part of it being interest from capital ownership and the other part being the entrepreneur's profit from the function of capital, and this is how it comes to be perceived.

Thus, money capitalists are opposed to functional capitalists, not to wage labor. This is because, although interest is born from the actual function of the capital production process, it is considered to be a product of capital ownership separate from it, and does not appear as a product of surplus labor. On the other hand, entrepreneurial profits are not opposed to wage labor, but are conceived only as being opposed to interest. This is because, if the average profit is given, the size of entrepreneurial profits is determined not by labor, but by the size of interest. Furthermore, entrepreneurial profits appear as the product of the capital function itself, that is, as the product of "labor" as the function of command and supervision of functional capitalists. Thus, entrepreneurial profits are further represented as "supervisory wages." Although the capital function has a capitalist character of acquiring surplus value and unpaid labor, it is replaced by the abstract function of command and supervision that can be found in any era.

In this way, the qualitative division of interest and entrepreneurial profits into their mutual independence conceals surplus value, even though they are the same, and causes the essence of capitalist production to be completely lost, and interest is also conceived in this way.

[Kaido Katsutoshi]

"Lessons on the System of Credit Theory" III (edited by the Credit Theory Study Group, 1956, Nippon Hyoronsha)" ▽ "Interest Theory by F.A. Lutz, translated by Joshima Kunihiro (1962, Ganshodo)" ▽ "Interest Rates by Adachi Tetsuo (1975, Financial and Fiscal Affairs Research Association)" ▽ "Textbook on Financial Theory" (edited by Hara Shiro, 1980, Yuhikaku)" ▽ "Capital Theory System 6: Interest and Credit (edited by Tomizuka Ryozo et al., 1985, Yuhikaku)" ▽ "Textbook Introduction to Finance" by Iwata Kikuo (2008, Toyo Keizai Shinposha)" ▽ "Capital by K. Marx, Volume 3, Part 5, Chapters 21-23 (translated by Mukaizaka Itsuro, Iwanami Bunko / translated by Okazaki Jiro, Otsuki Shoten, Kokumin Bunko)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

資金を一定期間貸し付けることに対する報酬。貸し付けた元金に対する利子の割合を利子率という。利子は利息、利子率は金利ともよばれる。

［原　司郎・北井　修］

近代経済学からみた利子

利子や金利は資金の貸借に応じて成立するから貨幣的とみられがちであるが、実物的な側面にたって利子や金利の資源配分に果たす役割を重視した見方も古くから唱えられてきた。たとえば、ベーム・バベルク、K・ウィクセルやI・フィッシャーたちがこの立場にたっている。すなわち、利子は、家計にとっては将来の消費に備えて貯蓄する一種の時間選好に対する報酬であるとする。現在の消費を犠牲にするのであるから、これに対して報酬（利子）が支払われるが、この利子率が高ければ高いほど、家計は貯蓄水準を高めようとする。また、企業は現在の生産を減少させても、一定の設備を増加させて将来の生産性を高めようとする。この結果、利益（利潤）が得られるので、この設備を増加させるための資金に利子を支払おうとする。これを企業の投資行動とよぶが、企業は投資行動に基づいて一定の利潤を得ることとなる。市場で資金を借り入れて支払う金利よりも投資に対する利潤率が高ければ、企業は投資を行うこととなる。家計の時間選好に基づく貯蓄と企業の投資の水準を決めるのは、前者が供給、後者が需要という関係で成立する市場での金利の高さで、この金利は実物的な利子率とみなすことができる。

　金利のもう一つの見方は貨幣的利子率であって、代表的な説明としてJ・M・ケインズの流動性選好説があげられる。すなわち、利子率は、人々が流動性という長所をもつ貨幣を手放して、債券のような利子を生む金融資産を保有することに対する報酬であると主張する。金利が高くなればなるほど、人々は貨幣をより多く手放して債券を保有しようとする。ケインズはこうして成立する貨幣利子率と資本の限界効率（設備投資を一単位増加させたときの期待収益率）の水準が一致するところで投資が決定されると主張した。

　利子率の決定理論としては、貸付資金説があげられる。貸付資金説は、貸付資金市場の資金需給関係によって成立する金利と、貨幣市場において貨幣の需給関係によって成立する金利との一般均衡によって金利水準が決まると主張する。

　なお、金利には名目金利と実質金利とがある。名目金利からインフレ率を差し引いたものが実質金利である。将来インフレ率が上昇すると市場が予想するときは、名目金利は上昇することとなる。

　以上述べてきたように、利子率は金融市場における需要と供給によって決定されるが、金融市場は、そこで取引される金融資産の多様化に応じていくつもの市場に分かれている。金融資産の満期という観点から分類すると、長期金融市場（資本市場）と短期金融市場（貨幣市場）とに大別されるが、それぞれの市場はさらに取引される金融資産ごとに細分される。そしてそれぞれの市場で金利が成立するから、現実の市場金利も多様である。この各種の金利の間にある種の規則性が存在するのではないかという見方がされるようになり、これを金利構造または金利体系とよんでいる。

　金利構造には、取引される金融資産の市場性の度合いやリスクの度合いによって各種金利の関係をとらえる見方もあるが、もっとも著名なものとして、金利の期間別構造がある。これは金融資産の満期に伴う各種金利の関係をみようとするもので、横軸に満期、縦軸に金利をとって、各種金利をつないだ利回り曲線yield curveが用いられる。利回り曲線は、流動性選好説によれば、長期資産のほうが流動性を手放す期間が長くなるので金利は高くなり、したがって右上がりの曲線となるが、将来の予想を重視する期待理論ではかならずしもそうはならない。すなわち、将来市場金利が上昇すると予想するときは、貸し手は短期資産の需要を強めるし、借り手は長期資産の供給を高める。そこで短期資産の価格は上昇し、利回りは低下するが、長期資産の価額は低下し、利回りは上昇する。この結果、短期資産の利回りが長期資産の利回りより低い右上がりの曲線となるが、市場が将来金利が下がると予想するときには反対に右下がりの曲線となる。

　金利の決定を自由化して市場にゆだねるとこのようにさまざまのタイプの利回り曲線が描けるが、政府や中央銀行が金利を規制すると多く場合は右上がりの曲線となる。日本では、第二次世界大戦後コールレートを除いてほぼすべての金利を規制してきた。また、人為的な低金利政策がとられてきた。この結果、資金の配分は金利ではなく、金融機関などによる信用割当てで行われてきた。そこで1980年代に入ると、先進各国よりは後れたものの、一連の金利自由化措置がとられた。1994年（平成6）10月の流動性預金の金利自由化により、現在では当座預金（付利禁止）を除く、すべての預金金利が自由化されている。貸出金利についても、1989年1月から各銀行が資金調達コストをベースに金融環境などを総合的に判断して決定する短期プライムレートの新方法が導入された。長期プライムレートについても、1991年4月から短期プライムレートに連動する長期変動貸出金利が導入されており、市場における資金の需給関係によって金利が決まるマーケットが形成されている。

［原　司郎・北井　修］

マルクス経済学からみた利子

貨幣は、資本主義生産のもとでは、貨幣それ自体の規定のほかに、自ら増殖して平均利潤を生む価値＝資本という使用価値をもつ商品となる。利潤をもたらす能力をもつこの貨幣を貨幣所有者が他人に譲渡すれば、後者は機能資本家となり、資本として機能する貨幣の使用価値に対して生産された利潤の一部分を支払う。これを利子という。もし貨幣が譲渡されないならば、機能資本家は利潤を生産できず、貨幣所有はその所有者に利潤の特定部分である利子の取得を与えない。したがって利子は、譲渡によって利潤を生むという使用価値をもった資本としての商品の価格、資本の価格として現象する。そしてその分量を規定するのが利子率である。

［海道勝稔］

利子率とその変動

利子率は、貸付可能な貨幣資本に対する利子の比率を表す。利子は機能資本家の平均利潤の一部であるから、その最高限は平均利潤そのものであり、最低限は無限にゼロに近い。利子率はこの限界内で貸付可能な資本に対する借り手（機能資本家）と貸し手（貨幣資本家）の需要・供給の関係のみで決まり、それ以外に利子率を決定する内的法則というものはない。

　産業資本、商業資本の平均利潤の現実の運動は、利子率の変動にその限界を与える以外には、利子率の変動とはなんの関係もない。つまり利子率は、担保の有無・種類・等級、貸付期間など借り手・貸し手の需要・供給に作用する要因によって相違し、時間的、場所的に絶えず変動する個々の市場利子率があるのみで、それがおのずから落ち着く自然利子率なるものはまったく存在しない。利潤率の個別的変動と違い、貸付可能資本に対する需要・供給が、総量として、相互に区別できない均一の形態として、また信用業の発達・集中に促進されて、同時大量的運動をとるからである。したがって利子率は、利潤率のような平均化傾向はもたず、はっきりと日々の経験のなかで直接にどの瞬間でも固定的につかまえられる大きさとして現れる。平均利子率、中位の利子率は算定されるのみであり、時間的には産業循環過程の利子率の変動の平均を算定し、場所的には資本が長期的に貸し出されるような利子率を算定することから得られるにすぎない。それは、生産過程・流通過程で貸付可能な資本の性格がなんの役割ももたないからである。利子率の決定は、需要・供給、習慣、法的伝統という偶然的、純経験的なものにすぎない。

　利子率は、不況期には、利潤率とともに一般にきわめて低い。好況期には、機能資本の意欲で漸次上昇し、繁忙期には、産業資本の投機的拡大で騰貴し、過剰生産になるや、利潤率は資本の還流が失われて急落し貨幣資本供給は減少するのに対し、金融はかえって逼迫(ひっぱく)するため、利子率はいっそう高騰する。恐慌時には、貨幣資本供給は激減するが、機能資本は自己の債務のため貨幣資本を求め、利子率は最高に急騰する。このように、産業循環の局面を決める利潤率に対して利子率の変動は同一ではない。

［海道勝稔］

利子と企業者利得

以上のように、利潤の一部を利子にするのは、資本家の貨幣資本家と機能資本家とへの社会的分裂によってだけである。したがって、借入れを行った機能資本家の平均利潤は、まず、貸し手の貨幣資本家に支払う利子と彼自身の分け前となる利子を超える超過分とに量的に分割される。

　ついで、両者の質的分割が始まる。機能資本家が貨幣資本家に支払う利子は、貨幣資本家が生産過程・流通過程で活動していないにもかかわらず、資本所有のゆえにそれに備わったものとして貨幣資本家にもたらされる果実、すなわち資本所有が直接生んだ部分と観念される。これに対し、平均利潤のうち機能資本家に帰属する利子を超える超過分は、彼の生産過程・流通過程での資本機能、すなわち企業者としての能動的役割におのずから備わり、そこから生ずると観念され、その果実として現れる。こうして同一の源泉でありながら、本質的に異なる二つの源泉から生じたように相互自立的現象をとる。

　この分裂が社会的に確定すると、借り入れない自己資本のもとでも、平均利潤を、一部は資本所有による利子とし、他は資本機能による企業者利得とする質的分割が生じ、そう観念されるようになる。

　こうして貨幣資本家は、機能資本家と対立して賃労働とは対立しない。なぜなら、利子は資本の生産過程の現実の機能から生まれたにもかかわらず、そこから離れた資本所有の産物であるとされ、剰余労働の産物としては現れないからである。他方、企業者利得も賃労働とは対立せず、利子とのみ対立するように観念される。なぜなら、平均利潤が与えられていれば、企業者利得の大きさは、労働によって、規定されないで、利子の大きさによって規定されるからである。さらに企業者利得は、資本機能そのものの所産として、すなわち、機能資本家の指揮・監督の機能としての「労働」の所産として現れる。かくして企業者利得は、さらに「監督賃金」の表象をとる。資本機能が、剰余価値、不払い労働の取得という資本主義的性格にあるのに、いつの時代にもみられる指揮・監督という抽象的機能に置き換えられてしまうのである。

　このようにして、利子と企業者利得への相互自立化による質的分割は、同じ剰余価値なのにそれを隠蔽(いんぺい)し、資本主義的生産の本質をまったく見失わさせ、利子もそう観念される。

［海道勝稔］

『信用理論研究会編『講座・信用理論体系』Ⅲ（1956・日本評論社）』▽『F・A・ルッツ著、城島国弘訳『利子論』（1962・巌松堂）』▽『阿達哲雄著『金利』（1975・金融財政事情研究会）』▽『原司郎編『テキストブック金融論』（1980・有斐閣）』▽『富塚良三他編『資本論体系6　利子・信用』（1985・有斐閣）』▽『岩田規久男著『テキストブック　金融入門』（2008・東洋経済新報社）』▽『K・マルクス著『資本論』第3巻第5篇第21～23章（向坂逸郎訳・岩波文庫／岡崎次郎訳・大月書店・国民文庫）』