📖 财政政策与货币政策的协调

Economics

I. Lesson Focus

This lesson examines how fiscal and monetary policies interact, the four primary policy mixes, their effects on real GDP, inflation, interest rates, and exchange rates, and the implications of central bank independence. Candidates must be able to analyze policy coordination within the IS-LM framework and evaluate crowding-out effects in both closed and open economies.

II. The Problem

Suppose an economy simultaneously experiences high unemployment and rising inflation. How should the government and central bank coordinate expansionary fiscal policy with monetary policy? If the central bank is highly independent, how will it respond to a large fiscal deficit? What are the systematic impacts of the four policy combinations (easy fiscal-tight monetary, tight fiscal-easy monetary, both easy, both tight) on output, price level, interest rates, and the currency? These questions form the core of the fiscal-monetary policy mix topic tested in CFA Level I Economics.

III. Tools and Transmission Mechanisms of Fiscal and Monetary Policy

Fiscal policy operates through government spending (G) and taxation (T). Expansionary fiscal policy increases G or cuts taxes, widening the budget deficit. Contractionary fiscal policy reduces G or raises taxes.

Monetary policy is conducted by the central bank using open-market operations, reserve requirements, and the policy rate. Expansionary monetary policy increases the money supply and lowers interest rates to stimulate investment and consumption. Contractionary monetary policy reduces the money supply and raises interest rates.

The transmission differs: fiscal policy directly shifts aggregate demand, while monetary policy works indirectly through interest rates and exchange rates. When coordinated, policy multipliers and crowding-out effects become critical.

IV. The Four Main Policy Combinations and Their Macroeconomic Effects

The four standard mixes are:

1. Expansionary Fiscal + Expansionary Monetary (Both Easy)
2. Aggregate demand rises sharply; real GDP increases significantly.
3. Inflationary pressures rise markedly.
4. Interest-rate effect is ambiguous (fiscal pushes rates up, monetary pushes them down).

5. Domestic currency usually depreciates.

6. Contractionary Fiscal + Contractionary Monetary (Both Tight)

7. Aggregate demand falls sharply; real GDP declines.
8. Inflation falls significantly.
9. Interest-rate effect is ambiguous.

10. Domestic currency usually appreciates.

11. Expansionary Fiscal + Contractionary Monetary (Easy Fiscal–Tight Monetary)

12. Real GDP grows moderately or stabilizes.
13. Inflation is contained.
14. Interest rates rise substantially (strong crowding-out).

15. Domestic currency appreciates (high rates attract capital inflows).

16. Contractionary Fiscal + Expansionary Monetary (Tight Fiscal–Easy Monetary)

17. Real GDP grows moderately.
18. Inflation remains mild.
19. Interest rates fall.
20. Domestic currency depreciates (capital outflows).

In the IS-LM model, fiscal policy shifts the IS curve and monetary policy shifts the LM curve. The relative slopes and magnitudes of the shifts determine the new equilibrium.

V. Central Bank Independence and Policy Conflict

When the fiscal authority runs large deficits, a highly independent central bank typically tightens monetary policy to neutralize inflationary pressure—this is known as policy offset. The result is higher interest rates, reduced private investment (crowding out), and a smaller fiscal multiplier.

If the central bank lacks independence, it may accommodate fiscal expansion through monetary financing, risking high or hyperinflation. CFA exams frequently test the “fiscal dominance versus monetary dominance” framework.

VI. Policy Mixes Across the Business Cycle

• Recessionary Gap: Both-easy or tight-fiscal/easy-monetary policies are preferred to avoid excessive inflation.
• Inflationary Gap: Both-tight or easy-fiscal/tight-monetary policies are used to stabilize prices while limiting output loss.
• Supply Shocks (e.g., oil crisis): Policy mixes must be chosen carefully to avoid exacerbating stagflation.

Worked Cases

Case 1: Both-Easy Policy in a Closed Economy

An economy has a GDP gap of –600 billion. MPC = 0.8. The government increases spending by 200 billion while the central bank expands the money supply to keep interest rates unchanged.

Fiscal multiplier = $1/(1-MPC)$ = $1/0.2$ = 5
Change in GDP = 200 × 5 = 1,000 billion
New GDP gap = –600 + 1,000 = +400 billion (inflationary gap appears).

Case 2: Easy-Fiscal/Tight-Monetary Policy — Interest Rates and Exchange Rates

In an open economy with perfect capital mobility, the government widens the deficit by 300 billion (IS shifts right) while the central bank raises the policy rate by 50 bp (LM shifts left).

Result:
- Equilibrium interest rate rises.
- Currency appreciates.
- Net exports decline, partially offsetting the fiscal stimulus.
- Real GDP increases only modestly and inflation is contained.

Case 3: Policy Conflict and Quantifying Crowding Out

The government plans to increase spending by 500 billion; the theoretical fiscal multiplier is 4. The central bank holds money supply constant (LM fixed). Investment interest-rate elasticity is –0.5 and the fiscal expansion raises rates by 2%.

Crowding-out of investment = 500 × 2% × 0.5 = 5 billion (simplified units).
Effective multiplier ≈ 4 × (1 – crowding-out proportion) ≈ 2.8.
Actual GDP increase = 500 × 2.8 = 1,400 billion instead of the theoretical 2,000 billion.

Traps

Key Formulas

• Closed-economy fiscal multiplier = $1/(1-MPC)$
• Effective multiplier after crowding out = theoretical multiplier × $(1 - \text{crowding-out proportion})$
• IS shift: $\Delta G \uparrow \rightarrow$ IS shifts right
• LM shift: Money supply $\uparrow \rightarrow$ LM shifts right
• Policy-mix matrix summary:
• Both easy → high growth, high inflation, currency depreciation
• Easy fiscal–tight monetary → moderate growth, low inflation, currency appreciation, high rates
• Tight fiscal–easy monetary → moderate growth, low inflation, currency depreciation, low rates
• Crowding-out magnitude = $\Delta r \times I_r$ (where $I_r$ = interest elasticity of investment)

Practice Questions

Q1. In the IS-LM model, simultaneous expansionary fiscal and monetary policy is most likely to result in:
A. Interest rates necessarily falling
B. Higher real GDP with ambiguous interest-rate movement
C. Lower price level
D. Necessary currency appreciation

Q2. When the government runs a large expansionary fiscal policy while the central bank pursues contractionary monetary policy, the most likely outcome is:
A. Significant crowding-out effect
B. Currency depreciation
C. Fiscal multiplier larger than theoretical value
D. Sharp rise in inflation

Q3. A tight-fiscal/easy-monetary policy mix is most likely to produce:
A. Higher interest rates and currency appreciation
B. Lower interest rates and currency depreciation
C. Sharp decline in real GDP
D. Significant increase in inflationary pressure

Q4. An economy suffering from stagflation would be best served by which policy mix?
A. Both easy
B. Both tight
C. Easy fiscal and tight monetary
D. Tight fiscal and easy monetary

Q5. If the central bank is highly independent, its most likely response to a large fiscal deficit is to:
A. Lower the policy rate
B. Purchase government bonds (monetize the debt)
C. Raise the policy rate to contain inflation
D. Keep monetary policy unchanged

Q6. In an open economy with perfect capital mobility, an easy-fiscal/tight-monetary policy mix will most likely cause the domestic currency to:
A. Depreciate
B. Appreciate
C. Remain unchanged
D. Move in an indeterminate direction

Q7. The fiscal multiplier is 5 and government spending increases by 100 billion. If complete crowding out occurs, the change in real GDP is:
A. +500 billion
B. +100 billion
C. Zero
D. –400 billion

Q8. Which policy mix is most likely to achieve both economic growth and low inflation simultaneously?
A. Both easy
B. Both tight
C. Expansionary fiscal and contractionary monetary
D. Contractionary fiscal and expansionary monetary

Answers

Takeaways

• Fiscal policy shifts IS; monetary policy shifts LM. Their relative movements determine equilibrium output and interest rates.
• Easy-fiscal/tight-monetary typically produces higher interest rates, currency appreciation, moderate growth, and contained inflation.
• Tight-fiscal/easy-monetary produces lower interest rates, currency depreciation, moderate growth, and mild inflation.
• Greater central-bank independence increases the likelihood of offsetting fiscal expansion and strengthens crowding-out.
• Actual fiscal multiplier is smaller than the theoretical multiplier when crowding out occurs; distinguish clearly in exam calculations.
• Mastery of the four-mix matrix (growth, inflation, rates, exchange rate) is essential for this topic.