A scaling limit for utility indifference prices in the discretised Bachelier model

Finance and Stochastics - We consider the discretised Bachelier model where hedging is done on a set of equidistant times. Exponential utility indifference prices are studied for path-dependent...     

From Bachelier to Dupire via optimal transport

Finance and Stochastics - Famously, mathematical finance was started by Bachelier in his 1900 PhD thesis where – among many other achievements – he also provided a formal derivation of...     

On the regulation of technology: Examining the linear model

The kind, magnitude and distribution of the risks borne by industrialized societies are determined by regulations and the effectiveness of their implementation and enforcement. The authors examine the paradox that the quantified, ‘hard’ risk estimates which provide the scientific basis for the linear model of regulation are, in fact, unrealistic because they are unable to deal with human and organizational influences on regulatory processes. The principal elements of regulation are discussed and placed in a more comprehensive and realistic perspective.     

On the analysis of a multi-threshold Markovian risk model

We consider a class of Markovian risk models perturbed by a multiple threshold dividend strategy in which the insurer collects premiums at rate c _i whenever the surplus level resides in the i-th surplus layer, i=1, 2, …,n+1 where n<∞. We derive the Laplace-Stieltjes transform (LST) of the distribution of the time to ruin as well as the discounted joint density of the surplus prior to ruin and the deficit at ruin. By interpreting that the insurer, whose gross premium rate is c, pays dividends continuously at rate d _i =c?c _i whenever the surplus level resides in the i-th surplus layer, we also derive the expected discounted value of total dividend payments made prior to ruin. Our results are obtained via a recursive approach which makes use of an existing connection, linking an insurer's surplus process to an embedded fluid flow process.     

On VIX futures in the rough Bergomi model

The rough Bergomi model introduced by Bayer et al. [Quant. Finance, 2015, 1–18] has been outperforming conventional Markovian stochastic volatility models by reproducing implied volatility smiles in a very realistic manner, in particular for short maturities. We investigate here the dynamics of the VIX and the forward variance curve generated by this model, and develop efficient pricing algorithms for VIX futures and options. We further analyse the validity of the rough Bergomi model to jointly describe the VIX and the SPX, and present a joint calibration algorithm based on the hybrid scheme by Bennedsen et al. [Finance Stoch., forthcoming].     

On the severity of ruin in a Markov-modulated risk model

We consider a Markov-modulated risk model in which the claim inter-arrivals, amounts and premiums are influenced by an external Markovian environment process. A system of Laplace transforms of the probabilities of the severity of ruin, given the initial environment state, is established from a system of integro-differential equations derived by Snoussi [The severity of ruin in Markov-modulated risk models Schweiz Aktuarver. Mitt., 2002, 1, 31–43]. In the two-state model, explicit formulas for probabilities of the severity of ruin are derived, when the initial reserve is zero or when both claim amount distributions are from the rational family. Numerical illustrations are also given.     

On the price of risk in a mean-risk optimization model

We investigate a mean-risk model for portfolio optimization where the risk quantifier is selected as a semi-deviation or as a standard deviation of the portfolio return. We analyse the existence of solutions to the problem under general assumptions. When the short positions are not constrained, we establish a lower bound on the cost of risk associated with optimizing the mean–standard deviation model and show that optimal solutions do not exist for any positive price of risk which is smaller than that bound. If the investment allocations are constrained, then we obtain a lower bound on the price of risk in terms of the shadow prices of said constraints and the data of the problem. A Value-at-Risk constraint in the model implies an upper bound on the price of risk for all feasible portfolios. Furthermore, we provide conditions under which using this upper bound as the cost of risk parameter in the model provides a non-dominated optimal portfolio with respect to the second-order stochastic dominance. Additionally, we study the relationship between minimizing the mean–standard deviation objective and maximizing the coefficient of variation and show that both problems are equivalent when the upper bound is used as the cost of risk. Additional relations between the Value-at-Risk constraint and the coefficient of variation are discussed as well. We illustrate the results numerically.     

On the role of market insurance in a dynamic model

Durables like cars or houses are a substantial component in the balance sheets of households. These durables are exposed to risk and can be insured in the market. We build a dynamic model in which agents have three possibilities to cope with the risk exposure of the durable stock: (i) purchase of market insurance, (ii) buffer-stock saving of the riskless asset or (iii) adjustment of the durable stock. We calibrate our model to the US economy and find a small role for market insurance.

On semiparametric estimation of ruin probabilities in the classical risk model

The ruin probability of an insurance company is a central topic in risk theory. We consider the classical Poisson risk model when the claim size distribution and the Poisson arrival rate are unknown. Given a sample of inter-arrival times and corresponding claims, we propose a semiparametric estimator of the ruin probability. We establish properties of strong consistency and asymptotic normality of the estimator and study bootstrap confidence bands. Further, we present a simulation example in order to investigate the finite sample properties of the proposed estimator.     

On the superneutrality of money in a stochastic dynamic macroeconomic model

This paper explores the robustness of the superneutrality of money result to the introduction of uncertainty. While, qualitatively, superneutrality fails to obtain in our model, quantitatively the observed Tobin effect is insignificant. The equilibrium time paths of real variables are nearly unaffected by changes in the money growth rule. We argue that our conclusions reinforce the theoretical case for superneutrality.     

论我国企业年金管理模式改革的战略方向

通过对我国企业年金管理模式纵横两方面的比较,本文认为,从微观的企业年金管理的层面上讲,法人受托模式下的2+2和3+1捆绑模式是目前企业年金管理的两种较好方式;从宏观的企业年金改革的层面上讲,企业年金管理改革的战略方向有四:从非信托模式走向信托模式;从理事会受托模式走向法人受托模式;从法人受托分拆模式走向法人受托捆绑模式;从传统金融机构捆绑模式走向养老金管理公司捆绑模式。     

On the relationship between the Poisson-exponential model and the non-central chi-squared distribution

Abstract

Two comments are made on the relationship between the Poisson-exponential model of insurance claims and the non-central chi-squared distribution. The first relates the Poisson-exponential to the recently introduced noncentral chi-squared on zero degrees-of-freedom; the second expands on the link between that distribution and the non-central chi-squared distribution on four degrees-of-freedom, noted by Boyle (1978).     

On the time series measure of conservatism: a threshold autoregressive model

In this note we propose an alternative test specification for Basu’s (1997) time series measure of conservatism that is related to the threshold unit root test of Enders and Granger (1998). We argue that a regression of changes in earnings on the lagged levels—rather than lagged changes—, including an interaction term for negative values, has three conceptual advantages compared to the conventional setup: (1) a smooth, non-oscillating impulse-response pattern to an unexpected shock in earnings (2) a more efficient estimate of persistence in the long run and (3) it can be extended to higher order autoregressive processes. We apply both approaches to a common dataset of firms from the S&P500 index. We confirm the conventional finding that negative shocks are transitory and display stronger mean reversion than positive shocks. However, while most of the literature reports mixed evidence on positive shocks, we find clear evidence that positive shocks are transitory as well. In a Monte Carlo simulation we explain this finding by documenting that larger standard errors in the Basu specification can lead to incorrect inference when the decision between persistent and transitory shocks is close.     

探索适应地方特色的小额信贷模式

中国小额信贷现状 我国农村小额信贷已经走过了14年的历程.目前,小额信贷在农村已成燎原之势,不仅项目的规模和范围在发展变化,而且形成了以政府部门与涉农金融机构合作开展的小额信贷为主,其他类型的小额信贷业务为辅的有中国特色的小额信贷体系.     

Determinants of audit report modifications in Finnish municipalities

Although municipalities are major economic and social actors in most countries, remarkably little is known about their audits, particularly the determinants of their audit report modifications. The existing evidence is ambiguous at best and scarce, which provides opportunities for further accounting studies in this area. Therefore, based on an agency theory framework, we fill this important research gap by exploring three determinants of audit report modifications in municipalities: (1) economic performance, (2) decentralization of decision-making across different decision-making bodies, and (3) political competition between political parties in local councils. These determinants are examined based on a large panel of data on Finnish municipalities for the period from 2009 to 2013, covering virtually all of the country’s municipalities. We find that a striking 33 percent of audit reports had modifications during this period, which raises serious concerns about the state of municipal management, accounting, and auditing in Finland. Regarding the above determinants, the following conclusions can be made based on our analyses. First, we find partial evidence that weak economic performance increases the likelihood of audit report modifications. Second, the lower the competition among political parties in a local council, the lower the likelihood of audit report modifications. Finally, the more decentralized decision making is across the different decision-making bodies under the local council, the higher the probability of audit report modifications. These results are consistent with agency theory’s explanations regarding the value of auditing.     

On portfolio optimization: forecasting covariances and choosing the risk model

We evaluate the performance of models for the covariance structureof stock returns, focusing on their use for optimal portfolioselection. We compare the models' forecasts of future covariancesand the optimized portfolios' out-of-sample performance. A fewfactors capture the general covariance structure. Portfoliooptimization helps for risk control, and a three-factor modelis adequate for selecting the minimum-variance portfolio. Undera tracking error volatility criterion, which is widely usedin practice, larger differences emerge across the models. Ingeneral more factors are necessary when the objective is tominimize tracking error volatility.     

On the exclusion of assets from tests of the two-parameter model: A sensitivity analysis

This study investigates the sensitivity of tests of the CAPM to different sets of asset returns. Tests are conducted with market portfolios that include returns for bonds, real estate, and consumer durables in addition to common stocks. Even when stocks represent only 10% of the portfolio's value, inferences about the CAPM are virtually identical to those obtained with a stocks-only portfolio. In contrast, inferences are sensitive to the set of assets used in the tests.     

On an efficient multiple time step Monte Carlo simulation of the SABR model

In this paper, we will present a multiple time step Monte Carlo simulation technique for pricing options under the Stochastic Alpha Beta Rho model. The proposed method is an extension of the one time step Monte Carlo method that we proposed in an accompanying paper Leitao et al. [Appl. Math. Comput. 2017, 293, 461–479], for pricing European options in the context of the model calibration. A highly efficient method results, with many very interesting and nontrivial components, like Fourier inversion for the sum of log-normals, stochastic collocation, Gumbel copula, correlation approximation, that are not yet seen in combination within a Monte Carlo simulation. The present multiple time step Monte Carlo method is especially useful for long-term options and for exotic options.