While extensive research has explored interconnectedness, volatility spillovers, and risk transmission across financial systems, the comparative dynamics between Islamic and conventional banks during crises, particularly in specific regions such as Saudi Arabia, are underexplored. This study investigates risk transmissions and contagion among banks operating in Islamic and conventional modes in the Kingdom of Saudi Arabia. Daily banking stock data spanning November 2018 to November 2023, encompassing two major crises—COVID-19 and the Russian-Ukraine war—were analyzed. Using the frequency TVP-VAR approach, the study reveals that average total connectedness for both banking groups exceeds 50%, with short-run risk transmission dominating over long-term effects. Graphical visualizations highlight time-varying connectedness, driven predominantly by short-run spillovers, with similar patterns observed in both Islamic and conventional banking networks. The main contribution of this paper is the insight that long-term investment strategies are crucial for mitigating potential risks in the Saudi banking system, given its limited diversification opportunities.

Catastrophes, like earthquakes, bring sudden and severe damage, causing fatalities, injuries, and property loss. This often triggers a rapid increase in insurance claims. These claims can encompass various types, such as life insurance claims for deaths, health insurance claims for injuries, and general insurance claims for property damage. For insurers offering multiple types of coverage, this surge in claims can pose a risk of financial losses or bankruptcy. One option for insurers is to transfer some of these risks to reinsurance companies. Reinsurance companies will assess the potential losses due to a catastrophe event, then issue catastrophe reinsurance contracts to insurance companies. This study aims to construct a valuation model for catastrophe reinsurance contracts that can cover claim losses arising from two types of insurance products. Valuation in this study is done using the Fundamental Theorem of Asset Pricing, which is the expected present value of the number of claims that occur during the reinsurance coverage period. The number of catastrophe events during the reinsurance coverage period is assumed to follow a Poisson process. Each impact of a catastrophe event, such as the number of fatalities and injuries that cause claims, is represented as random variables, and modeled using Peaks Over Threshold (POT). This study uses Clayton, Gumbel, and Frank copulas to describe various dependence characteristics between random variables. The parameters of the POT model and copula are estimated using Inference Functions for Margins method. After estimating the model parameters, Monte Carlo simulations are performed to obtain numerical solutions for the expected value of catastrophe reinsurance based on the Fundamental Theorem of Asset Pricing. The expected reinsurance value based on Monte Carlo simulations using Indonesian earthquake data from 1979–2021 is Rp 10,296,819,838.

Due to the bounded rationality of decision-makers and the substitution effect of non-green products, retailers are not always profitable when selling green products. To assist retailers who may be disadvantaged in the game, this study constructs a two-stage green supply chain game model, considering the bounded rationality of decision-makers and the substitution effect of non-green products, and analyzes the impacts of two operational strategies that retailers can adopt—price-cutting strategy and early replenishment strategy. The research reveals that retailers tend to lower prices in the second stage when price reductions stimulate consumer purchases, enhancing their profitability. However, strategic retailers may raise prices in the first stage to create room for discounts later, potentially harming consumer interests. Contrary to expectations, anticipating future demand does not always improve supply chain profitability in the early replenishment strategy, which mainly depends on the market environment. Early replenishment deprives retailers of negotiation leverage in the second stage, and bulk orders may lead manufacturers to over-invest in green innovation. Therefore, this strategy is effective only when green innovation costs are low, consumer environmental awareness is high, or price sensitivity is low.

Although infrastructure is widely recognized as a key ingredient in a country’s economic success, many issues surrounding infrastructurespending are not well understood. This paper explores six themes: the returns to infrastructure; the role of the private sector; the evaluation and delivery of infrastructure in practice; the nature of network industries, pricing and regulation; political economy considerations of infrastructure provision; and infrastructure in developing countries. This paper aims to provide insights into many of these questions, drawing on the existing literature.