The present research aims to evaluate impacts of crude oil price return index, Bloomberg Petroleum Index and Bloomberg energy index on stock market returns of 121 companies listed in Tehran stock exchange in a 10 years' period from early 2006 to April 2016. First, explanatory variables were aligned with petroleum products index mostly due to application of dollar data. Subsequently, to check va...

We examine the relationship between CEO ownership and stock market performance. Firms in which the CEO voluntarily holds a considerable share of outstanding stocks outperform the market by more than 10 percent p.a. after controlling for traditional risk factors. The effect is most pronounced in firms that are characterized by large managerial discretion of the CEO. The abnormal returns we docum...

Dairy wastewater is enriched in organic matter (about 45-72 g/l, COD) and also contains biodegradable carbohydrates. A three-stage system, NRBC was fabricated as a bench scale unit for lab experiments, to remove organic carbon from the whey. The fabricated NRBC had several advantages, such as quick start-up, high biomass concentration and was additionally able to handle high organic loading rat...

This research identifies returns to scale (RTS) of efficient decision making units (DMUs) with desirable (good) and undesirable (bad) inputs and outputs by presenting a new DEA (data envelopment analysis) approach. In this study, we first introduce a new input-output oriented model to determine efficient DMUs in the presence of undesirable factors and then, returns to scale of these DMUs are es...

I propose a new measure of common, time-varying tail risk for large cross sections of stock returns. Stock return tails are described by a power law in which the power law exponent is allowed to transition smoothly through time as a function of recent data. It is motivated by asset pricing theory and is estimable via quasi-maximum likelihood. Estimates indicate substantial time variation in sto...

evaluate the performance of companies on the stock exchange using non-parametric methods is very important. dea and dea-r with the strategies for piecewise linear frontier production function and use of available data, assess the stock company. in this study, using a neural network algorithm dea and dea-r is suggested to classify the first companies in the stock exchange; secondly, using the co...

We compare the effects, on rural wages and farmer income, of public investments in either a traditional or a modern agricultural sector. The traditional sector has constant or decreasing returns to scale. Economies of scale that are external to farms in the modern sector create a possible engine for growth. We show that if there are moderate returns to scale in the modern sector, and labor has ...