Upload
pauline-barrett
View
220
Download
1
Tags:
Embed Size (px)
Citation preview
Econ 208
Marek KapickaLecture 15
Financial Intermediation
Announcements
PS5 will be posted today, due next Thursday before the section (3pm) Give them directly to Xintong, or to
her mailbox Read “Zero sum debate” – the
Economist article about capital taxation
Why Financial Crises?
Key insight: Banks are here to transform illiquid assets to liquid liabilities Depositors prefer to withdraw deposits
easily (preference for liquidity) Borrowers need time to repay the loans
Tension between both sides of the balance sheet: If everyone wants to withdraw deposits,
there is not enough resources
A Liquidity Problem How to choose between liquid and
illiquid assets? Liquid assets: can be converted into
immediate consumption without any costs
Illiquid assets: it is costly to convert them into immediate consumption
People have preference for liquidity: they are unsure when they need to consume
A Liquidity ProblemTiming
Time Two assets:
Liquid, short-term (short) asset unit of consumption in period t can be converted
to unit of consumption in period Illiquid, long-term (long) asset
unit of consumption in period can be converted into units of consumption in period
Long asset yields more in the long run, but nothing in the short run!
A Liquidity ProblemPreferences
Liquidity preference: Two types of consumers: Early consumers: only want to
consume in period 1 Late consumers: are indifferent about
the timing of consumption The consumer learns about his
type at the beginning of period
An Example of Early Consumers
A Liquidity ProblemPreferences
Probability of being early: Preferences of a consumer:
expected utility
Trade-off: investing in long asset yield higher return but does not insure against the risk of being an early consumer
𝜃𝑈 (𝐶1)+(1−𝜃 )𝑈 (𝐶1+𝐶2)
A Liquidity Problem
1. Autarkic Solution2. Market Solution3. Efficient Solution4. Banking Solution
1. Autarkic Solution
The consumer has initial wealth Invests fraction in the short
(liquid) asset
Chooses to maximize
𝜃𝑈 (𝜆 )+ (1−𝜃 )𝑈 (𝜆+(1−𝜆 ) 𝐹 )
1. Autarkic SolutionThe Budget Constraint
1
1
𝐶1
𝐶2
𝐹
1. Autarkic Solution
If the utility is logarithmic, the solution is
If increases, increases If increases, decreases
𝜆=min [𝜃
1−1𝐹
¿,1]¿
A Liquidity Problem
1. Autarkic Solution2. Market Solution3. Efficient Solution4. Banking Solution
2. A Market SolutionMarket vs. Autarky
In a market, early consumer are allowed to sell long assets and buy short assets
We don’t have time to go through this, but one can show: Market can achieve more risk sharing
than autarky We will see that with banks we can do
even better than that
2. A Market SolutionMarket vs. Autarky
1
1
𝐶1
𝐶1+𝐶2
𝐹
Autarkic choices
Market Equilibrium
A Liquidity Problem
1. Autarkic Solution2. Market Solution3. Efficient Solution4. Banking Solution
3. The Efficient SolutionWhat is efficiency?
Pareto Efficiency: What would a social planner, not bound by markets, do?
Social planner: Choose feasible consumption Choose the amount and the society
invests in illiquid (long) and liquid (short) assets𝑥+𝑦=1
3. The Efficient SolutionSocial planner’s problem
Social planner: Maximize the expected utility
Subject to
WLOG assume that late consumers only consume in period 2
𝜃𝑈 (𝐶1)+(1−𝜃 )𝑈 (𝐶2)
3. The Efficient SolutionSocial Planner’s problem
Social planner: Maximize the expected utility
First order condition
max𝑥𝜃𝑈 ( 1−𝑥𝜃 )+ (1−𝜃 )𝑈 ( 𝐹𝑋
1−𝜃)
𝑈 ′ (𝐶1)=𝐹𝑈 ′(𝐶2)
3. The Efficient SolutionCase 1: Too little liquidity in the market solution
1
1
𝐶1
𝐶2
𝐹
Market Equilibrium
𝐶1∗
𝐶2∗
Efficient Solution
3. The Efficient SolutionCase 2: Too much liquidity in the market solution
1
1
𝐶1
𝐶2
𝐹
Market Equilibrium
𝐶1∗
𝐶2∗
Efficient Solution
3. The Efficient SolutionCase 3: The right amount of liquidity in the market solution
1=𝐶1∗
1
𝐶1
𝐶2
𝐹=𝐶2∗
Market Equilibrium = Efficient solution
3. The Efficient SolutionWhat next?
In general, the market solution is not efficient
How to get efficiency? Can banking improve on the market
solution?
A Liquidity Problem
1. Autarkic Solution2. Market Solution3. Efficient Solution4. Banking Solution
5. Banking SolutionA note on Information Structure
It is reasonable to assume that agent’s type is private information Only the agent knows if he is early or
late No one else cannot observe it
The (late) agents will not want to misrepresent their type if . This inequality holds in the efficient
allocation
5. Banking Solution
A bank Collects depositors’ investments at
time 0 Invests in a portfolio Offers to pay consumers (A deposit
contract) Free entry into the banking sector
Banks maximize investors’ expected utility
5. Banking SolutionEquilibrium without runs
Later on, we’ll see that banks are prone to runs, but ignore it for now
The bank maximizes the expected utility
Subject to
𝜃𝑈 (𝐶1)+(1−𝜃 )𝑈 (𝐶2)
5. Banking SolutionEquilibrium without runs
Maximize the expected utility
First order condition
Identical to the social planner’s problem
The (good) equilibrium is efficient!
max𝑥𝜃𝑈 ( 1−𝑥𝜃 )+ (1−𝜃 )𝑈 ( 𝐹𝑥
1−𝜃)
𝑈 ′ (𝐶1)=𝐹𝑈 ′(𝐶2)
5. Banking SolutionEquilibrium without runs
To make the problem interesting, we assume that
We also assume that the illiquid asset can be liquidated in period 1 to yield
𝑈 (𝐶 )=𝐶1−𝜎
1−𝜎,𝜎>1
5. Banking SolutionEquilibrium without runs
1
1
𝐶1
𝐶2
𝐹
𝐶1∗
𝐶2∗
Equilibrium without runs
5. Banking SolutionEquilibrium with runs
Assume that the bank operates under a sequential service constraint: Everyone who comes to the bank in
period 1 is paid , until bank resources are depleted
The liquidated value of all the bank’s assets is𝑆= 𝑓𝑥+𝑦 ≤ 𝑥+𝑦=1
5. Banking SolutionEquilibrium with runs
Suppose that everyone decides to withdraw in period 1
Since
1. Not everyone in can be paid in period 1
2. Those who wait until period 2 will get nothing
The bank will become insolvent
𝐶1>1≥𝑆
5. Banking SolutionEquilibrium with runs
A payoff matrix: late consumer (rows) vs every other late consumer (columns):
Note: the run/run payoff is the expected payoff
There are two equilibria: No run/No run (good equilibrium) Run/Run (bad equilibrium)
Run No Run
Run
No Run