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JAIIB Paper 1 • Indian Economy & Indian Financial System (IE&IFS)

Theories of Interest

One of the most conceptually tricky topics in JAIIB — why does the rate of interest exist, and what determines it? This guide covers the Classical Theory of Rate of Interest, Keynes' Liquidity Preference Theory, the Money Demand Curve, Money Market Equilibrium, the Effect of an Increase in Money Supply, Shifts in the Liquidity Preference Curve, and the Hicks-Hansen IS-LM Model — with diagrams, comparison tables, memory tricks and 50 exam-style MCQs with hidden answers.

📅 Updated: September 2026 • 27 min read

📊 At a Glance

Two rival schools of thought explain why interest rates exist and what moves them. Keep this core contrast in mind as you read the full article:

BasisClassical TheoryKeynes' Liquidity Preference Theory
Nature of interestA "real" phenomenonA "monetary" phenomenon
Reward forSaving / waiting (thrift)Parting with liquidity
Determined bySupply of savings = Demand for investmentDemand for money = Supply of money
Note: This page builds directly on our Economics Fundamentals, Demand & Supply guide (Money Supply, M1–M4) and connects to RBI & Monetary Policy (how RBI actually moves interest rates via the repo rate).

1 Classical Theory of Rate of Interest

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A "Real" Theory

The Classical Theory of Interest (associated with classical/neo-classical economists such as Marshall and Pigou) holds that the rate of interest is a purely real phenomenon, determined entirely by the interaction of the supply of savings and the demand for investment — with no independent role for money.

The Two Building Blocks

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Supply of Savings

Interest is the reward for "thrift" — postponing present consumption. Higher interest rates encourage more saving, so the savings curve slopes upward with the interest rate.

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Demand for Investment

Firms invest up to the point where the marginal efficiency of capital equals the interest rate (cost of funds). As more is invested, returns diminish, so the investment-demand curve slopes downward.

Equilibrium: The rate of interest is fixed at the level where planned Savings (S) = Investment (I) — the point where the upward-sloping savings curve intersects the downward-sloping investment-demand curve. This is why the classical approach is also called the "Saving-Investment" or "Loanable Funds" theory of interest in its extended (neo-classical) form.

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Memory Trick: "Save Up, Invest Down"
The Savings curve slopes Up; the Investment-demand curve slopes Down. Their crossing point fixes the classical rate of interest.
JAIIB tip — main criticism: The classical theory assumes an economy always operates at full employment and ignores the independent role of money and liquidity in setting interest rates — this is exactly the gap Keynes' theory (Section 2) was built to fill.

2 Keynes' Liquidity Preference Theory of Rate of Interest

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A "Monetary" Theory

John Maynard Keynes, in his 1936 work The General Theory, rejected the classical view. He argued that interest is not a reward for saving/waiting, but a purely monetary phenomenon — the reward for "parting with liquidity" for a specified period. People hold their wealth as cash (the most liquid asset) rather than bonds/other assets, and interest is what compensates them for giving up that liquidity.

Liquidity Preference = Demand for Money — Three Motives

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Transactions Motive

Cash held to meet day-to-day expenses (bridging the gap between receiving and spending income). A function of the level of income.

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Precautionary Motive

Cash held to meet unforeseen contingencies/emergencies. Also a function of income.

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Speculative Motive

Cash held to take advantage of expected future changes in bond prices/interest rates. A function of the interest rate itself — the interest-sensitive component.

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Memory Trick: "Tea, Please, Sir!"
Transactions, Precautionary, Speculative — the three motives behind the demand for money (liquidity preference).

Formally: Total money demand L = L1(Y) + L2(r), where L1 (transactions + precautionary) depends on income (Y), and L2 (speculative) depends inversely on the interest rate (r).

3 Money Demand Curve

Plotting the interest rate against the quantity of money demanded gives a downward-sloping money demand curve — driven almost entirely by the speculative motive.

Why the Curve Slopes Downward

  • High interest rate: Bond prices are low. People expect bond prices to rise (rates to fall) in future, so they prefer to hold bonds (to earn capital gains) over idle cash → speculative demand for money is low.
  • Low interest rate: Bond prices are high. People fear a future price fall (capital loss) and interest income is meagre anyway, so they prefer to hold cash → speculative demand for money is high.
Interest Rate (r) Money (M) Md
JAIIB tip: At very low interest rates, the money demand curve can become almost horizontal (perfectly elastic) — this extreme case is known as the "Liquidity Trap," where further monetary expansion fails to lower interest rates any further.

4 Determination of Rate of Interest — Equilibrium in the Money Market

Under Keynes' framework, the rate of interest is determined in the money market, at the point where the downward-sloping money demand curve (Md/Liquidity Preference) intersects the money supply curve (Ms).

Since the money supply is fixed by the central bank (RBI) at a point in time, Ms is drawn as a vertical line — perfectly inelastic with respect to the interest rate.

Interest Rate (r) Money (M) Md Ms r* E

At the equilibrium interest rate r*, the quantity of money demanded exactly equals the fixed quantity of money supplied — nobody wishes to hold more or less cash than what is actually available.

5 Effect of an Increase in Money Supply

When RBI expands the money supply (e.g., via an OMO purchase or a CRR cut), the Ms curve shifts rightward (to a higher fixed quantity). This is exactly how expansionary monetary policy transmits into lower market interest rates:

  1. At the old equilibrium interest rate, money supply now exceeds money demand (excess liquidity in the system).
  2. People holding this "excess" cash use it to buy bonds, since idle cash earns nothing.
  3. Increased demand for bonds pushes bond prices up.
  4. Since bond prices and interest rates move inversely, this means interest rates fall.
  5. Interest rates keep falling until a new, lower equilibrium rate restores Md = new Ms.
JAIIB tip: This is the textbook logic behind why an OMO purchase or a CRR cut (both of which raise Ms) is expansionary and pushes market interest rates down — directly linking this theory chapter to the practical RBI tools covered in our RBI & Monetary Policy guide.

6 Shifts in Money Demand / Liquidity Preference Curve

Unlike a change in the interest rate (which causes movement along the Md curve), a change in income (Y) shifts the entire liquidity preference curve — because transactions and precautionary demand (L1) depend on income, not the interest rate.

ChangeEffect on Md CurveEffect on Interest Rate (given fixed Ms)
National income (Y) risesShifts right (more transaction/precautionary demand)Rises
National income (Y) fallsShifts left (less transaction/precautionary demand)Falls

Intuition: When the economy is booming and incomes rise, households and firms need more cash on hand for everyday transactions — at a given (fixed) money supply, this extra demand for liquidity bids the interest rate up. This income-driven shift is precisely the link that connects the money market to the goods market — formalised next in the IS-LM model.

7 Hicks-Hansen Synthesis — IS-LM Curve Model

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Goods Market + Money Market, Together

Economist Sir John Hicks (1937), later extended by Alvin Hansen, combined Keynes' goods market analysis (savings-investment) and money market analysis (liquidity preference) into one unified two-curve diagram — the IS-LM model — determining income (Y) and the interest rate (r) simultaneously.

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IS Curve — "Investment = Saving"

Traces combinations of income (Y) and interest rate (r) at which the goods market is in equilibrium. Downward sloping: a lower interest rate boosts investment, which raises equilibrium income via the multiplier.

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LM Curve — "Liquidity = Money Supply"

Traces combinations of Y and r at which the money market is in equilibrium (money demand = fixed money supply). Upward sloping: higher income raises transactions demand for money, which — with Ms fixed — pushes the interest rate up.

Interest Rate (r) Income (Y) IS LM E (Y*, r*)

The point where IS and LM intersect gives the unique combination of income and interest rate at which both the goods market and the money market clear simultaneously. Fiscal policy (government spending/taxation) shifts the IS curve; monetary policy (changing money supply) shifts the LM curve — making IS-LM the standard framework for analysing how fiscal and monetary policy jointly affect income and interest rates.

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Memory Trick: "IS Falls, LM Climbs, Fiscal Shifts IS, Money Shifts LM"
IS slopes down (from the goods market), LM slopes up (from the money market). Fiscal policy moves IS; monetary policy moves LM. Their crossing point is the joint macro-equilibrium (Y*, r*).
JAIIB tip: The IS-LM model is also called the Hicks-Hansen model or the "Neo-Keynesian synthesis" — remember both names, as JAIIB questions may use either.

✓ Key Takeaways

  • Classical Theory: Interest is a "real" reward for saving; determined where Savings = Investment.
  • Keynes' Liquidity Preference Theory: Interest is a "monetary" reward for parting with liquidity; driven by three motives — Transactions, Precautionary, Speculative.
  • The Money Demand (Md) Curve slopes downward mainly due to the speculative motive; it can flatten out entirely in a Liquidity Trap.
  • Interest rate is determined where Md = Ms in the money market; Ms is a vertical line, fixed by RBI.
  • An increase in money supply lowers interest rates (via higher bond demand → higher bond prices → lower yields) — the core transmission logic of expansionary monetary policy.
  • A rise in income shifts the Md curve right, raising the equilibrium interest rate (given a fixed money supply).
  • The Hicks-Hansen IS-LM Model unifies the goods market (IS, downward sloping) and the money market (LM, upward sloping) to jointly determine income and the interest rate.

📝 Top 50 JAIIB-Style MCQs on Theories of Interest

Test your understanding with these 50 practice MCQs, closely modelled on the JAIIB (IE & IFS) exam pattern. Each question has 5 options — the correct answer is hidden by default; tap "Show Answer" to reveal it along with a short explanation.

đŸē Classical Theory of Rate of Interest
1 The Classical Theory of Interest treats interest as fundamentally a:
A. Monetary phenomenon
B. Real phenomenon
C. Fiscal phenomenon
D. Regulatory phenomenon
E. Random phenomenon
Answer: B. The classical view treats interest as a real, not monetary, phenomenon.
2 Under the Classical Theory, interest is regarded as a reward for:
A. Parting with liquidity
B. Saving / postponing consumption (thrift)
C. Bearing inflation risk
D. Holding foreign currency
E. Paying taxes
Answer: B. Classical theory sees interest as the reward for saving/thrift.
3 Under the Classical Theory, the equilibrium rate of interest is determined where:
A. Money demand equals money supply
B. Savings equal Investment
C. Exports equal Imports
D. Tax revenue equals expenditure
E. Bond demand equals bond supply
Answer: B. Classical equilibrium interest rate is where planned Savings = Investment.
4 In the Classical model, the savings curve, plotted against the interest rate, slopes:
A. Downward
B. Upward
C. Vertically
D. Horizontally
E. It does not exist
Answer: B. Higher interest rates encourage more saving — an upward-sloping curve.
5 In the Classical model, the investment-demand curve, plotted against the interest rate, slopes:
A. Upward
B. Downward
C. Vertically
D. Horizontally
E. It does not exist
Answer: B. Higher interest rates raise the cost of capital, discouraging investment — a downward-sloping curve.
6 A major criticism of the Classical Theory of Interest is that it:
A. Gives too much importance to money supply
B. Ignores the role of money/liquidity and assumes full employment
C. Only applies to developing countries
D. Was developed by Keynes
E. Cannot explain saving behaviour at all
Answer: B. Classical theory is criticised for ignoring money's role and assuming full employment.
💷 Keynes' Liquidity Preference Theory
7 Keynes' Liquidity Preference Theory treats interest as fundamentally a:
A. Real phenomenon
B. Monetary phenomenon
C. Purely fiscal matter
D. Foreign exchange matter
E. Legal matter
Answer: B. Keynes treats interest as a purely monetary phenomenon.
8 According to Keynes, interest is the reward for:
A. Saving
B. Parting with liquidity
C. Bearing default risk only
D. Holding gold
E. Paying off debt early
Answer: B. Keynes defines interest as the reward for parting with liquidity.
9 Keynes' Liquidity Preference Theory was presented in his landmark work:
A. Wealth of Nations
B. The General Theory of Employment, Interest and Money
C. Das Kapital
D. Principles of Economics
E. Value and Capital
Answer: B. Keynes presented this theory in his 1936 "General Theory."
10 Which of the following is NOT one of Keynes' three motives for holding money?
A. Transactions motive
B. Precautionary motive
C. Speculative motive
D. Taxation motive
E. None; all three listed above are correct motives
Answer: D. There is no "taxation motive" among Keynes' three motives.
11 The motive for holding money to bridge the gap between receiving income and spending it is the:
A. Speculative motive
B. Transactions motive
C. Precautionary motive
D. Investment motive
E. Growth motive
Answer: B. This is the transactions motive.
12 Cash held to meet unforeseen emergencies is held under the:
A. Speculative motive
B. Transactions motive
C. Precautionary motive
D. Fiscal motive
E. None of these
Answer: C. This is the precautionary motive.
13 Cash held to profit from expected future changes in bond prices/interest rates is held under the:
A. Speculative motive
B. Transactions motive
C. Precautionary motive
D. Consumption motive
E. None of these
Answer: A. This is the speculative motive.
14 The transactions and precautionary motives for holding money are primarily a function of:
A. The interest rate
B. The level of income
C. The exchange rate
D. The fiscal deficit
E. The CRR
Answer: B. Transactions/precautionary demand (L1) depends on income.
📉 Money Demand Curve
15 The money demand (liquidity preference) curve, plotted against the interest rate, is typically:
A. Upward sloping
B. Downward sloping
C. Perfectly vertical always
D. A perfect circle
E. Unrelated to interest rates
Answer: B. The money demand curve slopes downward with respect to the interest rate.
16 The downward slope of the money demand curve is mainly attributable to the:
A. Transactions motive
B. Precautionary motive
C. Speculative motive
D. Fiscal motive
E. Growth motive
Answer: C. The speculative motive drives the inverse relationship with the interest rate.
17 At high interest rates, speculative demand for money tends to be:
A. High, as people prefer cash
B. Low, as people prefer bonds expecting future price gains
C. Exactly zero always
D. Infinite
E. Unrelated to bond prices
Answer: B. High rates mean low bond prices; people expect gains and prefer bonds over cash.
18 The extreme situation where the money demand curve becomes almost horizontal at very low interest rates is called:
A. Liquidity Trap
B. Fiscal Trap
C. Poverty Trap
D. Inflation Trap
E. Currency Trap
Answer: A. This scenario is known as the Liquidity Trap.
⚖ī¸ Determination of Rate of Interest
19 Under Keynes' theory, the equilibrium rate of interest is determined where:
A. Savings equal Investment
B. Money demand equals money supply
C. Exports equal imports
D. Fiscal deficit equals zero
E. Bank deposits equal bank credit
Answer: B. Keynesian equilibrium interest rate is where money demand = money supply.
20 In the money market diagram, the money supply (Ms) curve is drawn as:
A. Downward sloping
B. Upward sloping
C. A vertical line
D. A horizontal line
E. A circle
Answer: C. Ms is fixed by the central bank and is drawn as a vertical line.
21 The money supply curve is drawn as a vertical line because it is assumed to be:
A. Perfectly elastic with respect to the interest rate
B. Perfectly inelastic with respect to the interest rate (fixed by the central bank)
C. Determined by the government's fiscal deficit
D. Equal to national income
E. Zero at all times
Answer: B. Ms is fixed exogenously by the central bank, independent of the interest rate.
📈 Effect of an Increase in Money Supply
22 An increase in the money supply, all else equal, will cause equilibrium interest rates to:
A. Rise
B. Fall
C. Remain exactly unchanged
D. Become negative always
E. Become infinite
Answer: B. A rightward shift in Ms lowers the equilibrium interest rate.
23 When money supply rises above money demand at the old interest rate, the excess cash is typically used to:
A. Buy bonds, raising bond prices
B. Sell bonds, lowering bond prices
C. Pay additional taxes
D. Reduce national income directly
E. Increase the fiscal deficit directly
Answer: A. Excess money is used to buy bonds, raising bond prices.
24 A rise in bond prices, all else equal, corresponds to:
A. A rise in interest rates/yields
B. A fall in interest rates/yields
C. No change in yields
D. A rise in the fiscal deficit
E. A fall in the money supply
Answer: B. Bond prices and yields (interest rates) move inversely.
25 Which RBI action, based on this theory, would be expected to LOWER market interest rates?
A. An OMO sale of government securities
B. A CRR hike
C. An OMO purchase of government securities
D. An SLR hike
E. A repo rate hike
Answer: C. An OMO purchase injects liquidity, raising Ms and lowering interest rates.
🔄 Shifts in the Liquidity Preference Curve
26 A rise in national income, with money supply held constant, causes the liquidity preference (Md) curve to:
A. Shift left
B. Shift right
C. Remain unchanged
D. Become vertical
E. Disappear
Answer: B. Higher income raises transactions/precautionary demand, shifting Md right.
27 A rightward shift of the Md curve, with Ms fixed, causes the equilibrium interest rate to:
A. Rise
B. Fall
C. Stay unchanged
D. Become zero
E. Become negative
Answer: A. More money demand at a fixed money supply pushes the interest rate up.
28 A fall in national income, with money supply held constant, would most likely cause equilibrium interest rates to:
A. Rise
B. Fall
C. Stay exactly the same
D. Become infinite
E. Turn negative permanently
Answer: B. Lower income reduces money demand, shifting Md left and lowering the interest rate.
🔗 Hicks-Hansen IS-LM Model
29 The IS-LM model was originally developed by:
A. Adam Smith
B. John Hicks
C. Milton Friedman
D. Irving Fisher
E. David Ricardo
Answer: B. John Hicks developed the IS-LM model in 1937.
30 The IS-LM model was later significantly extended and popularised by:
A. Alvin Hansen
B. Paul Samuelson only
C. Karl Marx
D. Alfred Marshall
E. Thomas Malthus
Answer: A. Alvin Hansen extended and popularised the model, hence "Hicks-Hansen."
31 The "IS" curve represents equilibrium in the:
A. Money market
B. Goods market (investment = saving)
C. Foreign exchange market
D. Labour market
E. Stock market
Answer: B. The IS curve represents goods-market equilibrium.
32 The "LM" curve represents equilibrium in the:
A. Goods market
B. Labour market
C. Money market (liquidity = money supply)
D. Foreign exchange market
E. Bond market only
Answer: C. The LM curve represents money-market equilibrium.
33 The IS curve, plotted with income on the X-axis and interest rate on the Y-axis, typically slopes:
A. Upward
B. Downward
C. Vertically
D. Horizontally
E. It has no defined slope
Answer: B. IS slopes downward: lower interest rates raise investment and equilibrium income.
34 The LM curve, plotted with income on the X-axis and interest rate on the Y-axis, typically slopes:
A. Downward
B. Upward
C. Vertically
D. Horizontally
E. It has no defined slope
Answer: B. LM slopes upward: higher income raises money demand, pushing the interest rate up given fixed Ms.
35 In the IS-LM framework, expansionary fiscal policy (e.g., higher government spending) primarily shifts:
A. The LM curve
B. The IS curve
C. Both curves by an identical amount
D. Neither curve
E. Only the Md curve
Answer: B. Fiscal policy shifts the IS curve.
36 In the IS-LM framework, expansionary monetary policy (an increase in money supply) primarily shifts:
A. The IS curve
B. The LM curve
C. Both curves equally
D. Neither curve
E. Only the savings curve
Answer: B. Monetary policy shifts the LM curve.
37 The point where the IS and LM curves intersect represents:
A. Equilibrium in the goods market only
B. Equilibrium in the money market only
C. Simultaneous equilibrium in both the goods market and the money market
D. Equilibrium in the foreign exchange market only
E. A point of permanent disequilibrium
Answer: C. The IS-LM intersection is a joint (simultaneous) equilibrium point.
38 The IS-LM model is also commonly referred to as the:
A. Classical Synthesis
B. Neo-Keynesian Synthesis
C. Monetarist Model
D. Supply-Side Model
E. Real Business Cycle Model
Answer: B. The IS-LM model is also called the Neo-Keynesian Synthesis.
🧩 Mixed / Comprehensive
39 Which theory of interest gives no independent role to the level of money supply?
A. Keynes' Liquidity Preference Theory
B. Classical Theory
C. IS-LM Model
D. All of the above equally
E. None of the above
Answer: B. The Classical Theory is a purely real theory, ignoring money supply.
40 Which theory explicitly incorporates the "speculative motive" for holding money?
A. Classical Theory
B. Keynes' Liquidity Preference Theory
C. Say's Law
D. FRBM framework
E. None of these
Answer: B. The speculative motive is a distinctly Keynesian concept.
41 Under the Classical model, an increase in the propensity to save (at every interest rate) would shift the savings curve:
A. Left, raising the equilibrium interest rate
B. Right, lowering the equilibrium interest rate
C. Neither shifts nor affects the interest rate
D. Vertically, with no interest rate effect
E. Into an investment curve
Answer: B. More saving at every rate shifts the savings curve right, lowering the equilibrium rate.
42 Which of the following best distinguishes the Classical Theory from Keynes' theory?
A. Classical uses a real (S=I) framework; Keynes uses a monetary (Md=Ms) framework
B. Classical is monetary; Keynes is real
C. Both are identical in every respect
D. Classical was developed after Keynes
E. Neither considers interest rates at all
Answer: A. This is the core distinction between the two theories.
43 In the money demand function L = L1(Y) + L2(r), the term L2(r) represents:
A. Transactions demand
B. Precautionary demand
C. Speculative demand
D. Government demand
E. Export demand
Answer: C. L2(r), the interest-sensitive component, is the speculative demand.
44 In the money demand function L = L1(Y) + L2(r), the term L1(Y) represents:
A. Speculative demand only
B. Transactions and precautionary demand combined
C. Total money supply
D. The fiscal deficit
E. Bond supply
Answer: B. L1(Y) is the income-dependent transactions plus precautionary demand.
45 A steep (near-vertical) LM curve implies that a given increase in money supply has:
A. A very large effect on the interest rate for a given change in income
B. No effect on interest rates under any circumstance
C. Only an effect on the fiscal deficit
D. An effect only on the IS curve
E. An effect only on exchange rates
Answer: A. A steep LM curve means interest rates respond strongly to changes in income/money supply.
46 If the money demand curve is completely flat (a liquidity trap), an increase in money supply will:
A. Sharply raise interest rates
B. Have little to no further effect on interest rates
C. Automatically raise national income
D. Cause deflation immediately
E. Shift the IS curve directly
Answer: B. In a liquidity trap, monetary expansion fails to push interest rates down further.
47 Bond prices and market interest rates share which type of relationship?
A. Direct (positive)
B. Inverse (negative)
C. No relationship
D. Only positive during recessions
E. Only negative during expansions
Answer: B. Bond prices and interest rates/yields move inversely.
48 Which theory of interest is generally regarded as more relevant to short-run monetary policy analysis by central banks like RBI?
A. Classical Theory
B. Keynes' Liquidity Preference Theory
C. Neither is used by central banks
D. Only fiscal theories are used
E. Only IS-LM in isolation, never Keynes' theory
Answer: B. Keynes' monetary approach underlies short-run policy analysis of how Ms changes affect interest rates.
49 The Hicks-Hansen IS-LM model is primarily useful for analysing:
A. Only long-run economic growth
B. The joint short-run effects of fiscal and monetary policy on income and interest rates
C. Only international trade balances
D. Only the exchange rate
E. Only agricultural output
Answer: B. IS-LM is the standard tool for joint fiscal-monetary policy analysis in the short run.
50 Which of the following correctly pairs each curve with the market it represents?
A. IS → Money market; LM → Goods market
B. IS → Goods market; LM → Money market
C. IS → Labour market; LM → Foreign exchange market
D. IS → Foreign exchange market; LM → Goods market
E. Both represent the same market
Answer: B. IS represents the goods market; LM represents the money market.

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Disclaimer: This article is prepared for educational and exam-preparation purposes only, based on standard macroeconomic theory as taught in the IIBF JAIIB syllabus. Candidates should cross-check the latest official IIBF syllabus before the exam.
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