Sources of the Money Supply | 货币供给的来源

📚 Sources of the Money Supply | 货币供给的来源

In economics, the money supply refers to the total stock of money held by the public in an economy at a given point in time. Understanding its sources is fundamental to analysing inflation, interest rates and monetary policy, particularly for Cambridge International A-Level Economics students.

在经济学中，货币供给是指一个经济体在特定时点由公众持有的货币总量。理解货币供给的来源，是分析通货膨胀、利率以及货币政策的基础，对于剑桥国际 A-Level 经济学考生尤为重要。

1. Defining Money Supply | 定义货币供给

The money supply is usually measured using monetary aggregates such as M0, M1, M2 and M3. Each aggregate includes different categories of money, from physical cash to highly liquid deposits and broader financial assets.

货币供给通常通过货币总量来测度，如 M0、M1、M2 和 M3。每个货币总量包含不同类别的货币，从实物现金到高流动性的存款，再到更广泛的金融资产。

In CIE A-Level Economics, students are expected to distinguish between narrow money (e.g. M0 and M1) and broad money (e.g. M2 and M3). Narrow money includes currency in circulation and demand deposits, while broad money adds savings deposits and time deposits.

在 CIE A-Level 经济学中，学生需要区分狭义货币（如 M0 和 M1）与广义货币（如 M2 和 M3）。狭义货币包括流通中的现金和活期存款，而广义货币则进一步加入储蓄存款和定期存款。

M0: notes and coins in circulation plus banks’ reserves at the central bank.
M0：流通中的纸币和硬币，加上商业银行在中央银行的准备金。
M1: M0 plus demand deposits held by the public.
M1：M0 加上公众持有的活期存款。
M2: M1 plus savings deposits and small time deposits.
M2：M1 加上储蓄存款和小额定期存款。
M3: M2 plus large time deposits and institutional money market funds.
M3：M2 加上大额定期存款和机构货币市场基金。

2. The Central Bank as a Source | 中央银行作为货币来源

The central bank is the sole issuer of legal tender currency. In the UK, this is the Bank of England; in many CIE syllabuses, the country is used as a case study. The central bank supplies banknotes and coins through its issue department.

中央银行是法定货币的唯一发行者。在英国，这一角色由英格兰银行承担；在许多 CIE 教学大纲中，英国被用作案例研究。中央银行通过其发行部门供应纸币和硬币。

When the central bank issues currency, it creates a liability in its balance sheet, while the corresponding asset is often a government bond, foreign exchange reserve or loan to commercial banks. This asset-backed issuance ensures confidence in the currency.

当中央银行发行货币时，它在资产负债表中产生一项负债，而对应的资产通常是政府债券、外汇储备或对商业银行的贷款。这种以资产为支持的发行机制保证了货币的信用。

Central bank balance sheet: Assets (bonds, reserves) = Liabilities (currency + commercial bank reserves)

中央银行资产负债表：资产（债券、储备）= 负债（通货 + 商业银行准备金）

3. Commercial Banks and Deposit Creation | 商业银行与存款创造

Commercial banks are the most important source of the money supply because they create money through lending. When a bank grants a loan, it credits the borrower’s account with a deposit, thereby increasing the total money supply.

商业银行是货币供给最重要的来源，因为它们通过放贷创造货币。当银行发放一笔贷款时，它会将借款人的账户贷方记入一笔存款，从而增加总货币供给。

This process is known as credit creation or the creation of bank deposits. It relies on the fractional reserve system, where banks keep only a fraction of deposits as reserves and lend out the rest.

这一过程被称为信用创造或银行存款创造。它依赖于部分准备金制度，即银行只保留存款的一定比例作为准备金，其余部分用于贷款。

4. High-Powered Money and the Monetary Base | 高能货币与基础货币

High-powered money, often called the monetary base or M0, consists of currency in circulation plus banks’ reserves held at the central bank. It is called “high-powered” because a change in this base leads to a multiplied change in the money supply.

高能货币，通常称为基础货币或 M0，由流通中的现金加上商业银行存放在中央银行的准备金构成。它之所以被称为”高能”，是因为基础货币变动会引起货币供给的倍数变动。

The relationship between the monetary base and the broader money supply is captured by the money multiplier. If the reserve ratio is 10%, a £1,000 increase in the monetary base can support up to £10,000 in total deposits.

基础货币与更广义货币供给之间的关系，可以用货币乘数来刻画。如果准备金率为 10%，基础货币增加 1,000 英镑，最多可以支持 10,000 英镑的总存款。

Money multiplier = 1 ÷ reserve ratio | 货币乘数 = 1 ÷ 准备金率

5. The Deposit Multiplier Process | 存款乘数过程

The deposit creation process can be illustrated with a simple example. Suppose a customer deposits £1,000 in Bank A. With a 20% reserve ratio, Bank A holds £200 and lends £800 to a borrower.

存款创造过程可以用一个简单例子来说明。假设一名客户在 A 银行存款 1,000 英镑。在 20% 的准备金率下，A 银行保留 200 英镑，并将 800 英镑贷给借款人。

The borrower spends the £800, and the seller deposits it in Bank B. Bank B holds £160 and lends £640. This process repeats, with each round creating smaller additional deposits. The total deposits created converge to £5,000.

借款人花掉这 800 英镑，卖方将其存入 B 银行。B 银行保留 160 英镑，贷出 640 英镑。这一过程不断重复，每一轮创造的额外存款递减。存款总额收敛至 5,000 英镑。

Round	New Deposit	Reserve (20%)	Loan
1	£1,000	£200	£800
2	£800	£160	£640
3	£640	£128	£512
Total	£5,000	£1,000	£4,000

6. Open Market Operations | 公开市场操作

Open market operations (OMOs) are a key source of money supply changes. When the central bank buys government bonds from commercial banks or the public, it pays for them by crediting their reserve accounts, thereby expanding the monetary base.

公开市场操作是货币供给变动的一个重要来源。当中央银行从商业银行或公众手中购买政府债券时，它通过贷记其准备金账户来付款，从而扩大基础货币。

Conversely, when the central bank sells bonds, it absorbs money from the banking system, reducing the monetary base. OMOs are the most frequently used monetary policy tool in advanced economies.

相反，当中央银行出售债券时，它从银行体系中吸收货币，减少基础货币。公开市场操作是发达经济体中最常用的货币政策工具。

Purchase of bonds: money supply increases.
购买债券：货币供给增加。
Sale of bonds: money supply decreases.
出售债券：货币供给减少。

7. Quantitative Easing | 量化宽松

Quantitative easing (QE) is an unconventional monetary policy where the central bank purchases long-term financial assets, such as government bonds and corporate bonds, on a large scale. This directly injects new money into the economy.

量化宽松是一种非常规货币政策，中央银行大规模购买长期金融资产，如政府债券和公司债券。这直接向经济中注入新货币。

During the 2008 financial crisis and the COVID-19 pandemic, the Bank of England and other major central banks used QE to increase the money supply and stimulate aggregate demand. QE is a direct source of money creation because it expands central bank reserves.

在 2008 年金融危机和新冠疫情时期，英格兰银行以及其他主要央行采用量化宽松来增加货币供给并刺激总需求。量化宽松是货币创造的直接来源，因为它扩大了中央银行的准备金。

8. Foreign Exchange Reserves | 外汇储备

In some economies, the money supply is also influenced by foreign exchange operations. When a central bank purchases foreign currency to prevent its domestic currency from appreciating, it pays by issuing domestic money, increasing the money supply.

在一些经济体中，货币供给也受到外汇操作的影响。当中央银行为防止本币升值而购买外币时，它通过发行本币来支付，从而增加货币供给。

This mechanism is particularly relevant in China, where the People’s Bank of China has historically sterilised such intervention by selling bonds to absorb excess liquidity. Sterilisation prevents the foreign exchange intervention from creating unwanted inflation.

这一机制在中国尤为重要，中国人民银行历来通过出售债券来冲销此类干预以吸收过剩流动性。冲销可以防止外汇干预造成不必要的通胀。

9. Government Borrowing and Money Supply | 政府借款与货币供给

Government borrowing can affect the money supply depending on who lends to the government. If the government sells bonds to the private sector or banks, existing money is transferred, but the total money supply does not change.

政府借款是否影响货币供给，取决于谁向政府放贷。如果政府向私人部门或银行出售债券，只是现有货币的转移，总货币供给不变。

However, if a government forces the central bank to buy its bonds directly, this is called monetising the debt. This creates new money and can lead to hyperinflation, as seen in some historical and developing-country cases.

然而，如果政府迫使中央银行直接购买其债券，这被称为债务货币化。这会创造新货币，并可能导致恶性通货膨胀，这在一些历史事件和发展中国家案例中可以看到。

10. Near Money and the Broad Money Supply | 准货币与广义货币供给

Beyond cash and bank deposits, there are financial assets that are easily convertible into money, such as treasury bills, certificates of deposit and money market deposits. These are called “near money” and appear in broader monetary aggregates.

除现金和银行存款外，还有易于转换为货币的金融资产，如国库券、大额存单和货币市场存款。这些被称为”准货币”，出现在更广义的货币总量中。

Although near money is not a direct source of spending, it affects liquidity in the financial system. A rise in near money can influence the money supply through changes in the behaviour of financial institutions and interest rates.

尽管准货币并非支出的直接来源，但它影响金融体系中的流动性。准货币上升可以通过金融机构行为和利率变化影响货币供给。

11. Limitations of the Money Multiplier | 货币乘数的局限性

In reality, the simple money multiplier is limited by several factors. Banks may hold excess reserves rather than lending all available funds, especially during economic uncertainty. This reduces money creation.

在现实中，简单的货币乘数受到若干因素的限制。银行可能会持有超额准备金而不是贷出所有可用资金，尤其是经济不确定时期。这会减少货币创造。

Additionally, the public may choose to hold more cash instead of depositing money in banks. This “cash drain” reduces the deposit base and weakens the multiplier effect. The actual money supply therefore depends on the decisions of banks and households, not just the central bank.

此外，公众可能选择持有更多现金而不是将钱存入银行。这种”现金漏损”减少了存款基础，削弱了乘数效应。因此，实际货币供给不仅取决于中央银行，还取决于银行和家庭的决策。

Actual money multiplier = (1 + cash ratio) ÷ (reserve ratio + cash ratio)

实际货币乘数 = (1 + 现金比率) ÷ (准备金率 + 现金比率)

12. CIE Exam Application | CIE 考试应用

In CIE A-Level Economics Paper 2 and Paper 4, examiners often ask candidates to explain how money is created by commercial banks, and to evaluate the effects of central bank policies on the money supply.

在 CIE A-Level 经济学试卷二和试卷四中，考官经常要求考生解释商业银行如何创造货币，并评价中央银行政策对货币供给的影响。

A strong answer will define the monetary base, explain the deposit multiplier with a numerical example, and discuss real-world limitations. Using a diagram of the money market can further illustrate how changes in money supply affect the interest rate and aggregate demand.

一份优秀的答案会定义基础货币，用数值例子解释存款乘数，并讨论现实中的限制。使用货币市场图表可以进一步说明货币供给变化如何影响利率和总需求。

Define key terms precisely: money supply, narrow money, broad money.
精确定义关键术语：货币供给、狭义货币、广义货币。
Explain the role of the central bank and commercial banks separately.
分别解释中央银行和商业银行的作用。
Use a step-by-step numerical example of deposit creation.
用逐步数值例子说明存款创造过程。
Evaluate with real-world limitations like excess reserves and cash drain.
结合超额准备金和现金漏损等现实局限进行评价。

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Sources of the Money Supply | 货币供给的来源