Hiroaki Hata

ORCID: 0000-0001-8593-3501
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About
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Research Areas
  • Stochastic processes and financial applications
  • Risk and Portfolio Optimization
  • Insurance, Mortality, Demography, Risk Management
  • Financial Risk and Volatility Modeling
  • Economic theories and models
  • Financial Markets and Investment Strategies
  • Probability and Risk Models
  • Insurance and Financial Risk Management
  • Complex Systems and Time Series Analysis
  • Physics and Engineering Research Articles
  • Flexible and Reconfigurable Manufacturing Systems
  • Credit Risk and Financial Regulations

Hitotsubashi University
2020-2023

Shizuoka University
2013-2019

Osaka University
2006-2012

Institute of Mathematics, Academia Sinica
2011

Academia Sinica
2010

We consider a long-term optimal investment problem where an investor tries to minimize the probability of falling below target growth rate. From mathematical viewpoint, this is large deviation control problem. This will be shown relate risk-sensitive stochastic for sufficiently time horizon. Indeed, in our theorem we state duality relation between above two problems. Furthermore, under multidimensional linear Gaussian model obtain explicit solutions primal

10.1214/09-aap618 article EN The Annals of Applied Probability 2010-01-08

We consider a consumption problem with an infinite time horizon to optimize the discounted expected power utility. The returns and volatilities of assets are random affected by some economic factors, modeled as diffusion process. becomes standard control problem. derive Hamilton--Jacobi--Bellman (HJB) equation study its solutions. In Part I, under weak conditions we prove existence solution for this HJB when assume ordered pair sub/supersolution. To construct sub/supersolution, also...

10.1137/110794845 article EN SIAM Journal on Control and Optimization 2012-01-01

Abstract We consider a finite-time optimal consumption problem where an investor wants to maximize the expected hyperbolic absolute risk aversion utility of and terminal wealth. treat stochastic factor model in which mean returns risky assets depend linearly on underlying economic factors formulated as solutions linear differential equations. discuss partial information case cannot observe process uses only past assets. Then our is control with information. derive Hamilton–Jacobi–Bellman...

10.1017/apr.2018.7 article EN Advances in Applied Probability 2018-03-01

We consider the Merton consumption problem on a finite time horizon to optimize discounted expected power utility of and terminal wealth in risk-averse cases. The returns volatilities assets are random affected by some economic factors, modeled as diffusion process. becomes standard stochastic control problem. derive Hamilton--Jacobi--Bellman (HJB) equation study its solutions. Under general conditions we construct suitable subsolution--supersolution pair. prove existence uniqueness solution...

10.1137/17m1135864 article EN SIAM Journal on Control and Optimization 2018-01-01

We consider an optimal consumption problem where investor tries to maximize the infinite horizon expected discounted hyperbolic absolute risk aversion utility of consumption. treat a stochastic factor model such that mean returns risky assets depend on underlying economic factors formulated as solution differential equation. Using dynamic programming principle, we derive Hamilton--Jacobi--Bellman (HJB) equation and study its solutions. In part I, prove existence classical for HJB under...

10.1137/110794857 article EN SIAM Journal on Control and Optimization 2012-01-01

The risk-sensitive asset management problem with a finite horizon is studied under financial market model having Wishart autoregressive stochastic factor, which positive-definite symmetric matrix-valued. This has the following interesting features: 1) it describes stochasticity of covariance structure, interest rates, and risk premium risky assets; 2) admits explicit representations solution to problem.

10.4236/jmf.2013.31a021 article EN Journal of Mathematical Finance 2013-01-01

In this paper, we consider the problem of optimal investment by an insurer. The wealth insurer is described a Cramér–Lundberg process. invests in market consisting bank account and m risky assets. mean returns volatilities assets depend linearly on economic factors that are formulated as solutions linear stochastic differential equations. Moreover, preferences exponential. With setting, Hamilton–Jacobi–Bellman equation derived via dynamic programming approach has explicit solution found...

10.1080/03461238.2017.1350876 article EN Scandinavian Actuarial Journal 2017-07-16

In this article, we consider a modification of the Karatzas–Pikovsky model insider trading. Specifically, suppose that agent influences long/medium-term evolution Black–Scholes type through drift stochastic differential equation. We say is using portfolio leading to partial equilibrium if following three properties are satisfied: (a) used by leads stock price which semimartingale under his/her own filtration and enlarged with final price; (b) optimal in sense it maximises logarithmic utility...

10.1080/14697688.2012.695084 article EN Quantitative Finance 2012-07-19

10.1007/s13160-017-0242-3 article EN Japan Journal of Industrial and Applied Mathematics 2017-03-07

<p style='text-indent:20px;'>We propose the stochastic factor model of optimal investment and reinsurance insurers where wealth processes are described by a bank account risk asset for Cramér-Lundberg process reinsurance. The optimization is obtained through maximizing exponential utility. Owing to claims driven Poisson process, proposed problem naturally treated as jump-diffusion control problem. Applying dynamic programming, we have Hamilton-Jacobi-Bellman (HJB) equations...

10.3934/mcrf.2021033 article EN Mathematical Control and Related Fields 2021-06-30

10.1007/s10690-020-09312-6 article EN Asia-Pacific Financial Markets 2020-07-18

10.1007/s13160-018-0318-8 article EN Japan Journal of Industrial and Applied Mathematics 2018-07-13

10.1007/s10690-023-09425-8 article EN Asia-Pacific Financial Markets 2023-10-03

In this paper, we are interested in the optimal investment and reinsurance strategies of an insurer with delay under $ 4/2 stochastic volatility model. Indeed, objective is to maximize expected power utility terminal wealth average on finite time horizon. The other growth rate per unit infinite described by approximation classical Cramér–Lundberg process. Then, these problems can be formulated as control delay. A pair forward-backward differential equations that derived via maximum principle...

10.3934/mcrf.2022055 article EN Mathematical Control and Related Fields 2022-12-07

10.1007/s13160-019-00396-w article EN Japan Journal of Industrial and Applied Mathematics 2019-11-04

In this paper, we give some numerical results related to Hata and Yasuda [1] that constructed an optimal investment reinsurance strategies of maximizing the expected power utility maximization problem for insurer. our experiments, use pathwise analysis Monte-Carlo simulation, compare four cases which have or do not reinsurance. And as performance criteria, adopt return, risk, Sharp ratio, terminal wealth, values their ranking.

10.5687/sss.2022.93 article EN Proceedings of the ISCIE International Symposium on Stochastic Systems Theory and its Applications 2022-03-31
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