银行间市场流动性与金融风险救助机制研究

文章从我国银行间市场结构特征出发,分析了近年来银行间市场利率和流动性大 幅波动的内在机理与原因。研究认为,塔形市场交易结构下,银行间市场存在流动性风险易聚 集不易分散的缺陷,且难以依靠“有形之手”得到弥补。文章结合塔形市场结构的特点建立矩 阵分析法,对40家金融机构资产负债表进行实证分析。结论印证了理论分析,即塔形市场交易 结构下风险冲击影响时间更长,且央行流动性救助效果降低,但流动性救助机制能降低风险对 中小型地方法人金融机构的冲击。因此,有必要建立流动性风险救助机制,弥补银行间市场客 观存在的缺陷,增强中小型地方法人金融机构抵御银行间市场流动性风险冲击的能力。     

Variations in Market Liquidity and the Intraday Interest Rate

Most central banks offer banks participating in large‐value real‐time gross settlement (RTGS) systems a free intraday overdraft facility to discourage banks from actively managing their daylight liquidity. In this paper, we ask whether this facility has kept the intraday interest rate at zero. Using a unique transaction‐level data set on collateralized interbank loans for 2006–12, we find that during periods of financial distress, rates for morning transactions are higher than those in the afternoon. Moreover, this intraday rate correlates with market liquidity, suggesting that rates contain a liquidity premium. This intraday pattern is reduced, but not eliminated by the Eurosystem's accommodative liquidity provision.     

Banks' Liquidity and the Cost of Liquidity to Corporations

We consider the liquidity shock banks experienced following the collapse of the asset‐backed commercial paper (ABCP) market in the fall of 2007 to investigate whether banks' liquidity conditions affect their ability to provide liquidity to corporations. We find that banks that borrowed more from the Federal Home Loan Bank system or the Federal Reserve's discount window following that liquidity shock passed a larger portion of their borrowing costs onto corporations seeking access to liquidity when compared to the precrisis period. This increase is larger among banks with a bigger exposure to the ABCP market, credit lines that pose more liquidity risk to banks, and borrowers that are likely dependent on the credit‐line provider. Our findings show that the crisis that affected the banking system had a negative effect not only on the price of credit to corporations, but also on the price corporations pay to guarantee access to liquidity.     

Interbank liquidity risk transmission to large emerging markets in crisis periods

In this paper, we conduct two investigations regarding funding liquidity risk in large emerging economies: Brazil, Russia, India, China, and South Africa — BRICS. In the first, we track the relevance of monetary policy decisions originating in developed economies for interbank funding liquidity risk in BRICS economies during crisis periods by applying a time-varying parameter model in a Bayesian framework. The results indicate weak associations between interbank credit market and US monetary policy and market conditions. In contrast, the Federal Reserve's National Financial Conditions Index (NFCI) — a representative of the health of both real and financial sectors in the US — matters more. The temporal patterns of the results imply that key central banking decisions precede or coincide with low degrees of associations. In the second, we examine whether interbank credit crunch exerts an influence on market liquidity risk in BRICS economies using a Granger causality approach. The results reveal that interbank credit crunch depresses market liquidity in the corresponding domestic market and that the state of fear and credit market conditions in the US exert some influence in this regard. Overall, our findings hint at judicious market intervention and liquidity management by BRICS central banks.     

Stock market liquidity and firm value

This paper investigates the relation between stock liquidity and firm performance. The study shows that firms with liquid stocks have better performance as measured by the firm market-to-book ratio. This result is robust to the inclusion of industry or firm fixed effects, a control for idiosyncratic risk, a control for endogenous liquidity using two-stage least squares, and the use of alternative measures of liquidity. To identify the causal effect of liquidity on firm performance, we study an exogenous shock to liquidity—the decimalization of stock trading—and show that the increase in liquidity around decimalization improves firm performance. The causes of liquidity's beneficial effect are investigated: Liquidity increases the information content of market prices and of performance-sensitive managerial compensation. Finally, momentum trading, analyst coverage, investor overreaction, and the effect of liquidity on discount rates or expected returns do not appear to drive the results.     

Trader Leverage and Liquidity

Does trader leverage drive equity market liquidity? We use the unique features of the margin trading system in India to identify a causal relationship between traders’ ability to borrow and a stock's market liquidity. To quantify the impact of trader leverage, we employ a regression discontinuity design that exploits threshold rules that determine a stock's margin trading eligibility. We find that liquidity is higher when stocks become eligible for margin trading and that this liquidity enhancement is driven by margin traders’ contrarian strategies. Consistent with downward liquidity spirals due to deleveraging, we also find that this effect reverses during crises.     

Dynamic portfolio optimization with liquidity cost and market impact: a simulation-and-regression approach

We present a simulation-and-regression method for solving dynamic portfolio optimization problems in the presence of general transaction costs, liquidity costs and market impact. This method extends the classical least squares Monte Carlo algorithm to incorporate switching costs, corresponding to transaction costs and transient liquidity costs, as well as multiple endogenous state variables, namely the portfolio value and the asset prices subject to permanent market impact. To handle endogenous state variables, we adapt a control randomization approach to portfolio optimization problems and further improve the numerical accuracy of this technique for the case of discrete controls. We validate our modified numerical method by solving a realistic cash-and-stock portfolio with a power-law liquidity model. We identify the certainty equivalent losses associated with ignoring liquidity effects, and illustrate how our dynamic optimization method protects the investor's capital under illiquid market conditions. Lastly, we analyze, under different liquidity conditions, the sensitivities of certainty equivalent returns and optimal allocations with respect to trading volume, stock price volatility, initial investment amount, risk aversion level and investment horizon.     

Investment timing and optimal capital structure under liquidity risk

Deterioration in debt market liquidity reduces debt values and affects firms' decisions. Considering such risk, we develop an investment timing model and obtain analytic solutions. We carry out a comprehensive analysis in optimal financing, default, and investment strategies, and stockholder–bondholder conflicts. Our model explains stylized facts and replicates empirical findings in credit spreads. We obtain six new insights for decision makers. We propose a ‘new trade-off theory’ for optimal capital structure, a new tax effect, and new explanations of ‘debt conservatism puzzle’ and ‘zero-leverage puzzle’. Failure in recognizing liquidity risk results in substantially over-leveraging, early bankruptcy or investment, overpriced options, and undervalued coupons and credit spreads. In addition, agency costs are surprisingly small for a high liquidity risk or a low project risk. Interestingly, the risk shifting incentive and debt overhang problem decrease with liquidity risk under moderate tax rates while they increase under high tax rates.     

流动性、银行间市场摩擦与借贷便利类货币政策工具

通过内生引入流动性短缺银行(拆入行)对流动性盈余银行(拆出行)的流动性需求机制,本文构建了一个包含银行间市场的DSGE模型,对借贷便利类货币政策工具的传导机制和传导效果进行了理论和实证研究。研究表明:(1)负向冲击会同时增加拆入行和拆出行对流动性的预防性需求,在经济形势不确定的情形下,拆出行不会很快恢复对拆入行的流动性供给,引起银行间市场流动性缺口放大和市场失灵。(2)由于仅依赖银行间市场自发回归稳态的过程太过缓慢,需要央行进行流动性干预。借贷便利类工具可以通过引导贷款市场定价和流动性效应这两个渠道来影响银行融资可得性,进而降低银行间市场流动性风险对宏观经济的负面影响。(3)借贷便利类货币政策工具的影响效果边际递减,央行可根据借贷便利操作的收益和成本,制定最佳的反应程度参数。     

流动性、银行间市场摩擦与借贷便利类货币政策工具

通过内生引入流动性短缺银行(拆入行)对流动性盈余银行(拆出行)的流动性需求机制,本文构建了一个包含银行间市场的DSGE模型,对借贷便利类货币政策工具的传导机制和传导效果进行了理论和实证研究。研究表明:(1)负向冲击会同时增加拆入行和拆出行对流动性的预防性需求,在经济形势不确定的情形下,拆出行不会很快恢复对拆入行的流动性供给,引起银行间市场流动性缺口放大和市场失灵。(2)由于仅依赖银行间市场自发回归稳态的过程太过缓慢,需要央行进行流动性干预。借贷便利类工具可以通过引导贷款市场定价和流动性效应这两个渠道来影响银行融资可得性,进而降低银行间市场流动性风险对宏观经济的负面影响。(3)借贷便利类货币政策工具的影响效果边际递减,央行可根据借贷便利操作的收益和成本,制定最佳的反应程度参数。     

Voluntary Reserve Targets

We study monetary policy implementation through an operating regime involving voluntary reserve targets (VRTs). Operating regimes based on reserve requirements may lead to a collapse in interbank trade, as they have since the financial crisis. We show that, no matter the abundance of reserves, VRTs encourage market activity and support the central bank's control over interest rates. We consider (i) the impact of anticipated and unanticipated liquidity injections by the central bank on market outcomes and (ii) a comparison with the implementation framework currently adopted by the Federal Reserve. Overall, a VRT framework may provide several advantages over other frameworks.     

The price of liquidity: The effects of market conditions and bank characteristics

We study the prices that individual banks pay for liquidity (captured by borrowing rates in repos with the central bank and benchmarked by the overnight index swap) as a function of market conditions and bank characteristics. These prices depend in particular on the distribution of liquidity across banks, which is calculated over time using individual bank-level data on reserve requirements and actual holdings. Banks pay more for liquidity when positions are more imbalanced across banks, consistent with the existence of short squeezing. We also show that small banks pay more for liquidity and are more vulnerable to squeezes. Healthier banks pay less but, contrary to what one might expect, banks in formal liquidity networks do not. State guarantees reduce the price of liquidity but do not protect against squeezes.     

Stock Liquidity Risk and the Cross‐sectional Earnings‐Returns Relationship

We argue that a higher sensitivity to aggregate market‐wide liquidity shocks (i.e., a higher liquidity risk) implies a tendency for a stock's price to converge to fundamentals. We test this intuition within the framework of the earnings‐returns relationship. We find a positive liquidity risk effect on the relationship between return and expected change in earnings. This effect on the earnings‐returns relationship is distinct from the negative effect observed for stock illiquidity level. Notably, the liquidity risk effect is evident (absent) during periods of neutral/low (high) aggregate market liquidity. We also show that the liquidity risk effect is dominant in firms that: (a) are of intermediate size; (b) are of intermediate book‐to‐market; and (c) are profit making.     

Option market making under inventory risk

We propose a mean-variance framework to analyze the optimal quoting policy of an option market maker. The market maker’s profits come from the bid-ask spreads received over the course of a trading day, while the risk comes from uncertainty in the value of his portfolio, or inventory. Within this framework, we study the impact of liquidity and market incompleteness on the optimal bid and ask prices of the option. First, we consider a market maker in a complete market, where continuous trading in a perfectly liquid underlying stock is allowed. In this setting, the market maker may remove all risk by Delta hedging, and the optimal quotes will depend on the option’s liquidity, but not on the inventory. Second, we model a market maker who may not trade continuously in the underlying stock, but rather sets bid and ask quotes in the option and this illiquid stock. We find that the optimal stock and option quotes depend on the relative liquidity of both instruments as well as on the net Delta of the inventory. Third, we consider an incomplete market with residual risks due to stochastic volatility and large overnight moves in the stock price. In this setting, the optimal quotes depend on the liquidity of the option and on the net Vega and Gamma of the inventory.      

Monetary Policy in a Low‐Inflation Environment: Developing a State‐Contingent Price‐Level Target

A number of academic studies find that either price‐level targeting or temporary above‐average inflation are nearly optimal policies to address a liquidity trap crisis. Still, central bankers and the public generally question whether even a temporarily higher inflation rate could be beneficial in addressing a liquidity trap or could be consistent with price stability over the longer term. At the same time, however, the Federal Reserve's projections for high unemployment and low inflation do not seem to be consistent with the best monetary policies to address the Fed's dual mandate responsibilities. Accordingly, it is useful to seriously discuss these potentially beneficial alternative policies.     

A Dilemma between Liquidity Regulation and Monetary Policy: Some History and Theory

History suggests a conflict between current Basel III liquidity ratios and monetary policy, which we call the liquidity regulation dilemma. Although forgotten, liquidity ratios, named “securities-reserve requirements,” were widely used historically, but for monetary policy (not regulatory) reasons, as central bankers recognized the contractionary effects of these ratios. We build a model rationalizing historical policies: a tighter ratio reduces the quantity of assets that banks can pledge as collateral, thus increasing interest rates. Tighter liquidity regulation paradoxically increases the need for central bank's interventions. Liquidity ratios were also used to keep yields on government bonds low when monetary policy tightened.     

THE DEALERS' PRICE/SIZE QUOTE AND MARKET LIQUIDITY

We model trading in a competitive securities market where informed traders and liquidity traders transact with dealers. The dealers' entire published quote is modeled: bid-ask prices and the number of shares the dealer is willing to buy/sell at these prices (i.e., size quotes). We argue that size quotes are a more informative indicator of market liquidity than the bid-ask spread's adverse-selection component. Moreover, the size quotes reveal several market characteristics that cannot be inferred from the bid-ask spread's adverse-selection component alone. The model generates a number of empirically testable predictions that clarify certain key elements of market liquidity.     

Option market liquidity: Commonality and other characteristics

This study examines option market liquidity using Ivy DB's OptionMetrics data. We establish convincing evidence of commonality for various liquidity measures based on the bid–ask spread, volumes, and price impact. The commonality remains strong even after controlling for the underlying stock market's liquidity and other liquidity determinants such as volatility. Smaller firms and firms with a higher volatility exhibit stronger commonalities in option liquidity. Aside from commonality, we also uncover several other important properties of the option market's liquidity. First, information asymmetry plays a much more dominant role than inventory risk as a fundamental driving force of liquidity. Second, the market-wide option liquidity is closely linked to the underlying stock market's movements. Specifically, the options liquidity responds asymmetrically to upward and downward market movements, with calls reacting more in up markets and puts reacting more in down markets.     

Capital Structure and Debt Priority

We study a defaultable firm's debt priority structure in a simple structural model where the firm issues senior and junior bonds and is subject to both liquidity and solvency risks. Assuming that the absolute priority rule prevails and that liquidation is immediate upon default, we determine the firm's interior optimal priority structure along with its optimal capital structure. We also obtain closed‐form solutions for the market values of the firm's debt and equity. We find that the magnitude of the spread differential between junior and senior bond yields is positively, but not linearly related to the total debt level and the riskiness of assets. Finally, we provide an in‐depth analysis of probabilities of default and the term structure of credit spreads.     

Scarcity of safe assets,inflation, and the policy trap

A goal of this paper is to make sense of the seemingly puzzling behavior of interest rates and inflation – and the role of central banks in that behavior – during and after the Great Recession, particularly in the United States. To this end, we construct a model in which government debt plays a key role in exchange, and can bear a liquidity premium. If asset market constraints bind, then there need not be deflation under an indefinite zero interest rate policy (ZIRP). Further, ZIRP may not be optimal under these circumstances. A Taylor-rule central banker could be subject to a ZIRP trap and persistently undershoot target inflation. As well, a liquidity premium on government debt creates additional Taylor rule perils, because of a persistently low real interest rate. We make a case that this is the key policy predicament currently faced by many central banks in the world.