درخت حوزه‌های تخصصی

As a key tool in implementing monetary policy and government financing, government bonds play an essential role in financial markets. By means of Islamic financial innovations in the Islamic capital market, the instrument of Islamic treasury bill is published and tradable in the over-the-counter market. Islamic treasury bills have many risks in terms of execution, including the ease of trading and liquidity in the secondary market. Therefore, this research aims to examine some microstructural elements of government bonds using a vector autoregressive model. In this article, the effect of trading volume on bid-ask spread of orders has been investigated. To survey the impact of these variables, the vector autoregressive (VAR) model has been used on intraday data of 17 symbols of Islamic treasury bills in the over-the-counter market, which had the most trading days from 2021 to September 2023. According to the studies, there is a significant relationship between the trading volume and bid-ask spread only in Islamic treasury bills with long-term maturity. Therefore, the effect of the bid-ask spread of orders in different periods is greater than the trading volume, especially in longer-term Islamic treasury bills. Hence, in this research, by analyzing the impulse response function, if there is a shock on the variables, the effect of the trading volume's shock remains for several periods and affects unremarkably the bid-ask spread of orders in most of the short-term and long-term Islamic treasury bills, while effects of the bid-ask spread shocks during initial periods for long-term and short-term Islamic treasury bills is excellent, but decrease sharply during the following periods. These results help traders pay attention and reduce the risk of trading in the over-the-counter market, specifically the long-term treasury bills.

This research aims to identify the effective factors on sustainable supply chain in the National Iranian South Oil Company (NISOC). The method of data collection was mixed methods. In the qualitative section, data were collected through reviewing 32 previous studies as well as in-depth interviews with 10 faculty members and experts in the field of sustainable supply chain of crude oil and oil products of the NISOC using a Non-Probability Judgmental Sampling. The main dimensions were identified from interviews, and the dimensions were grouped in 13 main categories and 78 sub-categories. 13 main components included organizational factors, production products, sustainable supply chain, industry supply chain, macro policies, technology, customer, economic factors, deficits of supply chain, social factors, political factors, organizational performance, and organizational productivity. Second, through reviewing literature and previous studies, 72 open codes in 9 categories were identified, including strategies, blockchain technology, improving the economic environment, improving the social and environmental policies and laws, internal organizational solutions, external organizational solutions, environmental management, market and capital factors. In the quantitative part, the researcher-made questionnaire was applied in a preliminary study on 10 experts in the field of management, and its relative content validity is examined. Then the final and modified version was provided to 384 employees of the NISOC. SmartPLS software were used for quantitative evaluation of the model. The presented model helps industry managers and decision makers to significantly improve the performance of the supply chain by re-designing the supply chain and taking appropriate measures.

The present study investigated weak-form market information efficiency in Tehran security exchange (TSE) as an emerging market and in Dow Jones United States security exchange (DJUS) as a developed market based on random walk model. In each market, the random walk model was examined using daily and monthly returns of a set of indices. The results of the parametric and non-parametric tests indicated that the daily returns are not independent and identically distributed in TSE. Moreover, according to the results of the variance ratio test, a trending behavior in daily returns and mean-reversion behavior in monthly returns were observed. In DJUS, however, the daily returns were found to be independent and identically distributed and the results of variance ratio test did not confirm that the returns follow a particular pattern in this market.