清华大学经济学原理(钱颖一)Chapter_26

Y – C – G =I
等式左边就是经济中支付消费和政府购买之后 的总收入，称为国民储蓄，或简称储蓄（S） The left side of the equation is the total income in the economy after paying for consumption and government purchases and is called national saving, or just saving (S).
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税收与储蓄 Taxes and Saving
减税增加了家庭在给定利率下进行储蓄的激励 A tax decrease increases the incentive for households to save at any given interest rate.
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储 蓄 Saving
假定有一个封闭经济——一个不从事 国际贸易的经济。 Assume a closed economy – one that does not engage in international trade:
Y=C+I+G
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储 蓄 Saving
现在，从等式两边同时减去C和G Now, subtract C and G from both sides of the equation:
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可贷资金市场 Market for Loanable Funds...
供给Supply
利率 Interest Rate
5%
需求Demand 可贷资金（十亿美元） Loanable Funds (in 20 billions of dollars)
0
$1,200
影响储蓄与投资的政府政策 Government Policies That Affect Saving and Investment 税收与储蓄 Taxe 政府预算赤字 Government budget deficits
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可贷资金市场的供给：储蓄 Supply of Loanable Funds: Saving
由于高利率使储蓄更有吸引力（当期消费更缺 乏吸引力），所以，随着利率的上升，可贷资 金的供给量增加。 Because a high interest rate makes saving more attractive, the quantity of loanable funds supplied rises as the interest rate rises. 可贷资金的供给曲线向右上方倾斜。 The supply curve for loanable funds slopes upward.
私人储蓄Y-C-T：税收T，利率r 公共储蓄T-G：政府支出G，税收T
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可贷资金市场的供给：储蓄 Supply of Loanable Funds: Saving
利率是借（贷）款的价格。 The interest rate is the price of the loan. 它代表借入者为贷款支付和借出者从储蓄中得 到的金额。 It represents the amount that borrowers pay for loans and the amount that lenders receive on their saving. 可贷资金市场上的利率是实际利率。 The interest rate in the market for loanable funds is the real interest rate.
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可贷资金市场的需求：投资 Demand for Loanable Funds: Investment
由于高利率使得借款更为昂贵，所以，随着利 率的上升，可贷资金的需求量减少。 Because a high interest rate makes borrowing more expensive, the quantity of loanable funds demanded falls as the interest rate rises. 可贷资金的需求曲线向右下方倾斜。 The demand curve for loanable funds slopes downward.
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公共储蓄 Public Saving
公共储蓄是政府支付了其支出之后的税 收收入。 Public saving is the amount of tax revenue that the government has left after paying for its spending.
Public saving ≡ (T – G)
第二十六章 储蓄、投资和金融体系 Saving, Investment, and the Financial System
储蓄与投资 Saving and Investment
储蓄与投资是GDP与生活水平长期增长的重要 决定因素。 Saving and Investment are important determinants of long-run growth in GDP and living standards. 宏观经济学家需要了解什么决定储蓄与投资， 特别是金融市场如何运作以及各类事件和政策 如何影响储蓄与投资。 Macroeconomists need to understand what determines saving and investment, especially how financial markets work and how various events and policies affect them.
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可贷资金市场的供给：储蓄 Supply of Loanable Funds: Saving
可贷资金的供给（S）来自于那些有多余收入 需要储蓄和贷出的人。 The supply of loanable funds comes from people who have extra income they want to save and lend out. 影响因素（收入Y给定）
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可贷资金市场 The Market for Loanable Funds
可贷资金指人们用来储蓄并借出、而不 是用于自己消费的所有收入 Loanable funds refers to all income that people have chosen to save and lend out, rather than use for their own consumption.
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可贷资金市场 The Market for Loanable Funds
金融市场协调经济中可贷资金市场上的储 蓄和投资。 Financial markets coordinate the economy’s saving and investment in the market for loanable funds.
私人储蓄是支付了税收和消费之后余下 的家庭收入。 Private saving is the amount of income that households have left after paying their taxes and paying for their consumption.
Private saving ≡ (Y – T – C)
S≡Y–C–G
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储 蓄 Saving
国民储蓄（或储蓄）等于： National saving, or saving, is equal to:
S≡Y–C–G S ≡ (Y – T – C) + (T – G)
特例：没有政府，G = T = 0，S ≡ Y - C
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私人储蓄 Private Saving
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储蓄与投资 Saving and Investment
以S代替Y-C-G，等式可以写成 Substituting S for Y-C-G, the equation can be written as:
S=I
对整个经济而言，储蓄必然等于投资。 For the economy as a whole, saving must be equal to investment.
通过假设经济当中只有单一的金融市场，我 们集中精力来解释金融市场如何协调整体经济 的储蓄与投资。 Assuming that the economy has a single financial market, we focus on explaining how financial markets coordinate the economy’s saving and investment as a whole.
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储 蓄 Saving
回忆GDP既是经济中的总收入，也是花在经 济中产品和服务的总产出上的总支出。 Recall that GDP is both total income in an economy and total expenditure on the economy’s output of goods and services: Y = C + I + G + NX 经济决定其既定收入（Y）在不同用途（包括 投资）的支出上的选择。 不过，经济中收入获得者（家庭）通常不直 接进行投资；而是作为资本的借出方——储蓄 者。
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可贷资金市场上的供给与需求 Supply and Demand for Loanable Funds
金融市场的运作和经济中的其他市场 非常相似。 Financial markets work much like other markets in the economy.
可贷资金的供求均衡决定了实际利率。 The equilibrium of the supply and demand for loanable funds determines the real interest rate.
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税收与储蓄 Taxes and Saving
对利息收入征税极大地减少了当前储蓄的 未来偿付，因而减弱了储蓄的激励。 Taxes on interest income substantially reduce the future payoff from current saving and, as a result, reduce the incentive to save.
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可贷资金市场的需求：投资 Demand for Loanable Funds: Investment
可贷资金的需求（I）来自于希望借入以 进行投资的家庭和企业。 The demand for loanable funds comes from households and firms that wish to borrow to make investments. 影响因素：利率(r)等。
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公共储蓄 Public Saving
如果T>G，政府有预算盈余，因为其得到的钱 多于其花掉的钱。 If T>G, the government runs a budget surplus because it receives more money than it spends. 盈余T-G代表公共储蓄。 The surplus of T-G represents public saving. 如果G>T ，政府有预算赤字，因为其花掉的 钱多于其得到的税收收入。 If G>T, the government runs a budget deficit because it spends more money than it receives in tax revenue.
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储蓄与投资 Saving and Investment
这个等式背后的机制是什么？ What mechanism lie behind this equality? 谁来协调储蓄者与投资者？ What coordinates savers and investors? 回答：金融体系。 Answer: The financial system.