Aggregate Bank Capital and Credit Dynamics

Transcription

1 Aggregate Bank Capital and Credit Dynamics N. Klimenko S. Pfeil J.-C. Rochet G. De Nicolò (Zürich) (Bonn) (Zürich, SFI and TSE) (IMF and CESifo) March 2016 The views expressed in this paper are those of the authors and do not necessarily represent those of the IMF. 1/34

2 MOTIVATION Financial regulators and central banks now control powerful macro-prudential tools for promoting systemic stability. Long-term impact on growth and financial stability? Standard DSGE models cannot really help: they were designed to reproduce short-term reactions of prices and output to monetary policy decisions. Monetary Policy and Macroprudential Policy have different objectives, different horizons and different instruments. To study the long-term impact of macro-prudential policies on output and financial stability, one needs a different type of model. We provide an example of such a model. 2/34

3 OUR CONTRIBUTION General equilibrium dynamic model with financial frictions, in the spirit of Brunnermeier-Sannikov (2014) and He-Krishnamurthy (2013). Banks are explicitly modeled. Bank capital serves as a loss-absorbing buffer and determines the volume of lending. Model allows the analysis of the long-run effects of minimum capital requirements on lending and systemic stability (ergodic distribution). Main implications are in line with empirical evidence. 3/34

4 RELATED LITERATURE 1. Macro-finance in continuous time Brunnermeier-Sannikov (2014, 2015), He-Krishnamurthy (2012, 2013), Di Tella (2015), Phelan (2015). 2. Welfare impact of capital requirements Van den Heuvel (2008) Martinez-Miera and Suarez (2014) DeNicolò-Gamba-Lucchetta (2014) Nguyen (2014) Begenau (2015) 4/34

5 ROADMAP 1. Model 2. Competitive equilibrium 3. Long run dynamics 4. Application to macro prudential policy analysis 5/34

6 MODEL General equilibrium model: real sector and banking sector. One physical good, can be consumed or invested. Households invest their savings in bank deposits and bank equity. Banks invest in (risky) loans to entrepreneurs and reserves (can be <0). Entrepreneurs have no capital and must borrow from banks, who monitor them: no direct finance. Central bank provides reserve and refinancing facilities to equilibrate the interbank lending market. 6/34

7 GLOBAL PICTURE Central bank Firms Loans Reserves Banks Liabilities (deposits, interbank loans, Interests on deposits Repayments Loans K t CB loans) Households Profits Equity E t Dividends Entrepreneurs Remark: equity acts as a buffer to guarantee safety of deposits (no deposit insurance) and interbank borrowings. 7/34

8 MODEL Households and entrepreneurs are risk neutral and discount future consumption at rate ρ. Interbank rate r is fixed and less than ρ. Households receive interest r D on deposits. At equilibrium r D = r. Households derive utility from holding riskless deposits (transactional demand for safe assets as in Stein (2012)). Supply of deposits is fixed and is a decreasing function of (ρ r). For simplicity, r 0 in this presentation. Easy to extend for r > 0. 8/34

9 MODEL: FIRMS Firms: can borrow 1 unit of productive capital from banks at time t, must repay 1 + R tdt at t + dt if borrow, produce xdt unit of good, where x is distributed over [0, R] with density f (x) borrow when x > R t; aggregate demand for loans is a decreasing function of loan rate R L(R) = R R f (x)dx productive capital is destroyed (default) with probability pdt + σ 0 dz t, where {Z t, t 0} is a standard Brownian motion (aggregate shocks) 9/34

10 MODEL: BANKS Aggregate shocks in the real sector translate into banks profits/losses Book equity of an individual bank evolves: de t = k t[(r t p)dt σ 0 dz t] }{{} return on a bank s loans dδ t }{{} dividends where k t is the volume of lending to firms at time t Aggregate bank equity evolves: de t = K t[(r t p)dt σ 0 dz t] }{{} return on total loans where K t is aggregate lending d t }{{} dividends + di }{{} t, recapitalizations + di }{{} t, recapitalizations Main friction: issuing new equity entails proportional cost γ 10/34

11 ONE-PERIOD EXAMPLE 2 dates: t = 0 and t = 1, length of time period h = 1. Firms default probability: { p σ 0, with probability 1/2 (positive shock) p + σ 0, with probability 1/2 (negative shock) At t = 0 a typical bank starts with equity e, may distribute dividends δ 0 or issue new equity i 0, borrows d > 0 from depositors, lends k. Main friction: issuing new equity entails proportional cost γ. 11/34

12 AN INDIVIDUAL BANK S PROBLEM At t = 1 profits/losses are realized, bank equity becomes: e + (e δ + i) + k [ R (p σ 0 ) ] e (e δ + i) + k [ R (p + σ 0 ) ], Bank capital must be sufficiently high to cover the worst possible loss: Shareholders problem: v = max δ,i,k { δ (1 + γ)i + e 0 ( 1 2 ) e + + ( θ) e 1 + ρ θ denotes the Lagrange multiplier associated with constraint e 0. }, 12/34

13 AN INDIVIDUAL BANK S PROBLEM Shareholders problem is separable: v = eu + max δ 0 δ[ 1 u ] + max i 0 where is the Market-to-Book ratio. FOCs: i [ u (1 + γ) ] + max k 0 u 1 + θ 1 + ρ 1 u 0 (= if δ > 0) [ (R p)(1 + θ) θσ0 ] k, 1 + ρ u (1 + γ) 0 (= if i > 0) R p θ (= if k > 0) R (p + σ 0 ) 13/34

14 AN INDIVIDUAL BANK S PROBLEM u 1 θ > 0 non-default constraint binds on individual and aggregate level Dividends are distributed (δ > 0) when E E max, where u(e max) = 1 New equity is raised (i > 0) when E E min, where u(e min ) = 1 + γ 14/34

15 ONE-PERIOD EXAMPLE: COMPETITIVE EQUILIBRIUM a) The loan rate R R(E) is a decreasing function of aggregate capital and it is implicitly given by E + L(R(E)) [ R(E) (p + σ 0 ) ] = 0 b) All banks have the same market-to-book ratio of equity that belongs to [1, 1 + γ] and is a decreasing function of aggregate capital. ( ) ( ) 1 σ 0 u(e) = 1 + ρ R(E) (p + σ 0 ) c) Banks pay dividends when E E max u 1 (1) and recapitalize when E E min u 1 (1 + γ). 15/34

16 ONE-PERIOD EXAMPLE: TAKE AWAY 1. Only the level of aggregate bank capital E matters for banks policies 2. Banks recapitalization and dividend policies are of the "barrier type" and are driven by the market-to-book value 3. Loan rate is decreasing in aggregate bank capital E 16/34

17 AN INDIVIDUAL BANK S PROBLEM Markovian competitive equilibrium: R t = R(E t) and K(E t) = L(R(E t)) An individual bank chooses lending, dividend and recapitalization policies to maximize shareholder value: v(e t, E t) = max k s,dδ s,di s [ + E t ] e ρ(s t) (dδ s (1 + γ)di s) Shareholder value is linear in e: v(e, E) eu(e), where u(e) is the Market-to-Book ratio. Only aggregate capital E matters for banks policies. 17/34

18 DIVIDEND AND RECAPITALIZATION POLICIES Dividend/recapitalization policies of a barrier type: banks distribute dividends when E t = E max, such that u(e max) = 1 banks recapitalize when E t = E min = 0 Emax E t Dividends Emin=0 Recapitalizations Remark: E max and E min are determined by equilibrium forces on the market for bank equity. 18/34

19 EQUILIBRIUM LOAN RATE Positive loan spread, decreasing with E: [ R(E) p = σ0k(e) 2 u (E) ], u(e) }{{} where u (E) < 0 lending premium Source of lending premium: implied risk-aversion of bankers with respect to variations in aggregate capital 19/34

20 COMPETITIVE EQUILIBRIUM (CE) Aggregate bank capital evolves according to: ] de t = L(R(E t)) [(R(E t) p)dt σ 0 dz t, with reflection at E min = 0 (recapitalizations) and E max (dividends) The loan rate function R(E) : [0, E max] [p, R max] solves R 2ρσ0 2 + (R p) 2 (E) = σ0 2[L(R) (R p)l (R)], R(Emax) = p R max and E max increase with financing friction γ 20/34

21 TESTABLE PREDICTIONS R( E) Loan rate u( E) 1+ γ MTB ratio of bank equity R max p 1 E min = 0 E max E E min = 0 E max E Testable predictions: equilibrium loan rate and market-to-book ratio are decreasing functions of aggregate capital E = = Emax min E 0 21/34

22 EMPIRICAL EVIDENCE: DATA DESCRIPTION Panel of publicly traded banks in 43 advanced and emerging market economies ( ): U.S. banks (728 banks) Japan (128 banks) Banks in advanced economies (248 banks) Japanese banks; banks in advanced economies (excluding the U.S. and Japan); banks in emerging market economies. Table 1 summarizes the denitions of the variables considered. Banks in emerging market economies (183 banks) Table 1: Denition of variables Identier Variable Measurement ret bank gross return on assets total interest income/earning assets mtb market-to-book equity ratio market equity/book equity logta bank size Log(assets) loanasset % of loans to assets total loans/total assets bequity bank book equity bank book equity npl non-performing loans non-performing loans in % of total assets T BE total bank equity sum of bequity Note that bank gross return on assets include revenues accruing from investments other than loans; however, in the analysis below we will condition our estimates on asset composition using the % of loans to assets as a bank control. Furthermore, total bank equity is the sum of the equity 22/34

23 EMPIRICAL EVIDENCE: SAMPLE STATISTICS Table 2: Sample statistics and unconditional correlations 48 Panel A: Sample Statistics US Japan Advanced (ex. US and Japan) Emerging V ariable Obs. Mean Std.Dev. Obs. Mean Std.Dev. Obs. Mean Std.Dev. Obs. Mean Std.Dev. ret mtb logta loanasset bequity (US$ billion) npl TBE (US$ billion) Panel B: Correlations ret mtb logta ret mtb logta ret mtb logta ret mtb logta mtb logta TBE Notes: indicates signicance at 5% level. 23/34

24 EMPIRICAL MODEL Y t = α + βe t 1 + γx t 1 + ηdummy t + ɛ t Focus on coefficient β (must be negative) Dependent variables: Y = (ret, mtb) Bank specific effects: X = (bequity, logta, loanasset, npl) Time-varying country specific effects: Dummy 24/34

25 EMPIRICAL EVIDENCE: CONDITIONAL CORRELATIONS 25/34

26 LOAN RATE DYNAMICS Loan rate R t = R(E t) has explicit dynamics dr t = µ(r t)dt + σ(r t)dz t, p R t R max, with σ(r) = 2ρσ2 0 + (R p) 2 ( σ 0 where h(.) is explicit. 1 (R p) L (R) L(R) ) and µ(r) = σ(r)h(r), 26/34

27 LONG RUN BEHAVIOR OF THE ECONOMY Full description of the long run behavior of the economy: stochastic steady state It is characterized by the ergodic density function of R or E (shows how frequently each state is visited in the long run) We can numerically solve for the ergodic density function of R (no need for simulations): g (R) g(r) = 2µ(R) σ 2 (R) 2σ (R), on [p, Rmax] σ(r) 27/34

28 LONG RUN BEHAVIOR OF THE ECONOMY Particular specification: linear demand for loans ( R R ) L(R) = where R > p R p 0.12 σ(r) g(r) 80 γ small γ large Rmax Rmin = p Rmin = p Rmax R R Remark: the long run behavior of the economy is driven by the endogenous volatility. 28/34

29 APPLICATION: MINIMUM CAPITAL RATIO What happens if banks are subject to a minimal Capital Ratio (CR) Λ? e t Λk t Maximization problem of an individual bank: v Λ(e, E) = max k t e Λ,dδ t,di t [ + ] E e ρt (dδ t (1 + γ)di t) 0 Homogeneity property is preserved: v Λ(e, E) eu Λ(E) We find that CR constraint binds for low E and is slack for high E. u Λ(.) and equilibrium loan rate R Λ(.) have different expressions in constrained (E < E Λ c ) and unconstrained (E E Λ c ) regions. 29/34

30 CAPITAL RATIO AND BANK POLICIES E R Impact of capital regulation 0.05 on the maximum 0.2 E max r + p loan rate Λ * = 44% Λ,% Λ E min Λ E c Λ E max Banks increase their target level of capital (E Λ max > E max) and recapitalize earlier (E Λ min > 0). Small and moderate Λ: both the unconstrained and constrained regimes co-exist. Very high Λ: the unconstrained region disappears (no extra capital cushions). 30/34

31 CAPITAL RATIO AND LENDING K(E) 1.00 CE Λ = 3 % Λ = 10 % SB E Banks reduce lending not only in the constrained region, but also in the unconstrained one Lending exposure to aggregate shocks endogenous volatility 31/34

32 EXPECTED TIME TO RECAPITALIZATION Tγ(E) Λ= E - Emin Λ Λ>0 Stability measure: T γ(e) - the average time to recapitalization starting from the average level of aggregate capital E Λ endogenous volatility + expected banks profits stability 32/34

33 CONCLUSION Tractable dynamic macro model where aggregate bank capital drives credit volume. Asymptotic behavior described by the ergodic distribution. Model permits simple analysis of macro-prudential policy. Further investigations: market activities complementary to lending, endogenous risk-taking, banks defaults. 33/34

34 Thank you! 34/34