Bedri Tas

• Boston College, Ph.D.
• Professor (Associate) at TOBB University of Economics and Technology

Bstract We examine the dynamic effects of uncertainty shocks on unemployment during recessions in the US. We estimate a Bayesian time-varying parameter structural vector autoregression. We analyze how the impact of uncertainty shocks on U.S. unemployment changes over time. We find that uncertainty shocks have both higher unit impact and higher tota...

This paper empirically identifies the optimal number of bidders to achieve the lowest procurement prices in public procurement auctions. We examine a unique data set that covers all Turkish government procurement auctions comprising more than half a million observations for the period 2005–2012. We present a novel and easy-to-implement method to in...

of the World Trade Organization (WTO) Government Procurement Agreement (GPA) on government procurement practices in the European Union (EU). We analyse empirically whether the WTO GPA is effective in promoting non-discriminatory, open, transparent, competitive, and cost-effective government procurement. To study this question, we use a unique data...

We examine the impact of the World Trade Organization (WTO) Government Procurement Agreement (GPA) on government procurement practices in the European Union (EU). We analyse empirically whether the WTO GPA is effective in promoting non-discriminatory, open, transparent, competitive, and cost-effective government procurement. To study this question,...

We characterize the dynamic network structure of major oil producing countries. We examine the oil production coordination of 13 Organization of the Petroleum Exporting Countries (OPEC) and 17 non-OPEC members. We construct the dynamic network structure using the network connectedness measure of Diebold and Yilmaz (2009). We investigate the structu...

We investigate how the forecasting performance of the Federal Reserve Greenbooks has changed relative to commercial forecasters between 1974 and 2009. To this end, we analyze time-variation in the Greenbook coefficients in forecast encompassing regressions. Assuming that model coefficients change continuously, we estimate unobserved components mode...

We investigate the credibility of inflation targeting (IT) central banks (CBs) by estimating perceived inflation targets of the financial markets. We calculate financial markets’ beliefs about the inflation targets of 24 IT countries. Then, we analyse whether the financial markets’ beliefs about inflation targets match the announced targets. We con...

We examine the change in the effect of Federal Reserve’s policy actions on stock returns after the Fed started to use unconventional policy actions. We find that the response of stock returns to monetary policy actions are almost seven times higher after the federal funds rate hit the zero lower bound. We conduct additional analysis to examine the...

We empirically examine international monetary coordination by identifying the network structure of four major central banks: The Bank of England, Bank of Japan, European Central Bank and Federal Reserve Bank. We calculate the time-varying connectedness measure developed by Diebold and Yilmaz (2005). Specifically, we investigate the interdependence...

This paper contributes to the ongoing debate about the existence and source of asymmetric information between the Federal Reserve and the public by examining the federal funds rate forecasts. It compares the Federal Reserve federal funds rate forecasts with the predictions of alternative forecasting models and forecasts from the futures market for...

The aim of this paper is to analyze the effect of monetary policy on stock returns and stock return variability in the Gulf Cooperation Council (GCC) countries namely; Bahrain, Kuwait, Oman, Qatar and Saudi Arabia (United Arab Emirates was excluded for non-availability of the data). The empirical results reveal that the impact of policy interest ra...

This article empirically investigates the economic effects of public e-procurement (PEP) adoption. We use a unique data set provided by the Public Procurement Authority of Turkey that covers all government procurement auctions for the years 2004–12, 588,454 auctions. We conclude that PEP adoption had adverse effects. The number of firms submitting...

In this study, we investigate two main research questions using unique individual trade level data from the Istanbul Stock Exchange (ISE; renamed Borsa Istanbul in January 2013): (1) Do brokers conduct manipulative trades in the ISE? (2) Do these brokers gain returns from their manipulative behavior? We examine the trade-based "pump-and-dump" price...

We investigate how the forecasting performance of the Federal Reserve Greenbooks has changed relative to commercial forecasters between 1974 and 2007. To this end, we analyze time-variation in the Greenbook coefficients in forecast encompassing regressions using two new methods, namely, Bayesian estimation and structural break estimation. Our analy...

El presente artículo investiga los efectos de la dolarización en el desempeño macroeconómico de una pequeña economía abierta, la de Ecuador, empleando para ello un análisis de series de tiempo. Específicamente, exploramos cómo la dolarización implementada en este país afectó la inflación, el pib, la incertidumbre inflacionaria y la relación entre e...

The goal of this study is to investigate the causal relationship between financial development and economic growth in Gulf Cooperation Council (GCC) countries i.e.: Bahrain, Oman, Kuwait, Qatar, United Arab Emirates and Saudi Arabia over the period 1980-2012. We employed panel unit root tests, and Error Correction Model and cointegration techniques...

This paper analyzes how effective macroeconomic policy actions are in ending recessions. We also investigate which structural factors help the country to experience shorter recessions. We implement survival regression analysis and conclude that expansionary monetary policy significantly decreases durations of recessions whereas fixing the exchange...

We investigate how the forecasting performance of the Federal Reserve Greenbooks has changed relative to commercial forecasters between 1974 and 2009. To this end, we analyze time ‐‑ variation in the Greenbook coefficients in forecast encompassing regressions. Assuming that model coefficients change continuously, we estimate unobserved components m...

We analyse the success of inflation targeting (IT) in decreasing inflation volatility by investigating inflation variance before and after IT. We contribute to the literature by implementing Markov-Switching AutoRegressive Conditional Heteroscedastic methodology to model inflation volatility. After determining the unbiased conditional variances of...

In the past decade, electronic mechanisms have started to overtake the conventional methods of procurement for both governments and enterprises because of the cost and time saving effects of e-procurement. Economic theory suggests that the success of e-procurement depends on the number of bidders who participate in procurement auctions. In this pap...

Different types of products are procured in government procurement auctions. This paper empirically analyzes the effect of competition (number of bidders) on procurement price of different types of products. In other words, we investigate the optimal number of bidders which minimizes procurement costs in auctions for services, goods and constructio...

This paper empirically investigates the impact of inflation targeting on inflation uncertainty. We implement PARCH and GARCH methodologies to model conditional variance of inflation. We also investigate the relationship between level and volatility of inflation to analyze the validity of the Friedman hypothesis for IT countries. We find that most o...

This paper empirically investigates the effect of the competitive environment (number of participants) on the cost of procurement. We use a unique dataset provided by the Public Procurement Authority (PPA) of Turkey that covers all of the government procurement auctions for the years 2004–2006. First, after controlling for possible endogeneity, we...

This paper investigates effects of macroeconomic conditions in an economy on government procurement (GP) auctions. Specifically, two research questions are examined: 1) What are the effects of macroeconomic variables on the competitive environment (number of bidders) in GP auctions? 2) How does the procurement price (winning bid in GP auctions) res...

Governance of market intermediaries is an integral component of efficient equity markets especially in emerging economies. In this study, we investigate two main research questions using a unique individual trade level data from the Istanbul Stock Exchange (ISE): Do brokers conduct manipulative behavior in the ISE? Do these brokers gain returns out...

This paper theoretically investigates optimal monetary policy regime for oil producing developing countries. We analyze credibility and reputation of the Central Bank and macroeconomic dynamics under alternative monetary policy regimes. We construct a detailed and realistic model that can be used to analyze macroecomic structure and expectation dyn...

In this paper, the impact of two service quality metrics (star rating and customer rating) on hotel room sales and prices is investigated. Two of the most popular tourist destinations in the world, Paris and London, are chosen. It is found that a higher customer rating significantly increases the online sales of hotels. The study results show that...

This paper theoretically investigates inflation targeting when there is asymmetric information between the Central Bank and the public. The main argument of this study is that the inflation target can be used as a signaling mechanism through which the private sector learns about the private information of the Central Bank about future inflation and...

This paper investigates the effects of dollarization on the macroeconomic performance of a small open economy, Ecuador, using a time series perspective. More specifically, we investigate how dollarization effects inflation, GDP, inflation uncertainty and money-price relationship in Ecuador. There are four main findings of this study. First, inflati...

Using theoretical and empirical analyses, this paper shows that the expectation dynamics induced by information asymmetry between the Central Bank (CB) and the public can cause the price puzzle. The signalling and learning dynamics between the CB and a representative private-sector agent under asymmetric information is investigated. Inflation posit...

This article investigates whether the Federal Reserve's (Fed's) private Gross Domestic Product (GDP) growth forecasts, as reported in the Greenbook of the Fed, contain information about future real and excess stock returns. I implement long-horizon regressions to analyse the predictive power of the Fed's GDP growth forecasts. The regressions conclu...

This paper analyzes how effective macroeconomic policy actions are in ending recessions. We also investigate which structural factors help the country to get out of recessions, in other words experience shorter recessions. We implement survival regression analysis and conclude that expansionary monetary policy significantly decreases durations of r...

In the past decade, electronic mechanisms have started to overtake the conventional methods of procurement for both governments and enterprises because of the cost and time saving effects of e-procurement. Economic theory suggests that the success of e-procurement depends on the number of bidders who participate in procurement auctions. In this pap...

This paper investigates the implicit inflation targets of inflation targeting (IT) CBs (CBs). This allows us to analyze whether the actions of the IT CBs coincide with their announced targets. The implicit (perceived) inflation targets of IT CBs derived from the actions (policy interest rates) are calculated before and after IT adoption. We constru...

This paper contributes to the ongoing debate about the existence and the source of asymmetric information between the Federal Reserve and the public by examining the federal funds rate forecasts. It shows that the Federal Reserve has superior information about its own future policy actions, the future federal funds rate. It compares the Federal Res...

This study empirically investigates which firms are more susceptible to successful manipulation. For this purpose, a unique dataset consisting of manipulation cases from 1998-2006 from the Istanbul Stock Exchange (ISE) were collected and firm-specific variables are used to explain these manipulations. Probit regression results show that small firms...

This paper examines whether the mechanism by which global shocks are transmitted into MENA countries changes over time. Three main questions are investigated by implementing TVC-VAR methodology. 1) Do MENA countries respond differently to global economic shocks? 2) Do the reactions of countries to global economic shocks vary over time? 3) What are...

This paper contributes to the ongoing discussion about the endogeneity of money supply by empirically investigating the GCC countries. We propose and implement a direct test of money supply endogeneity that depends on econometric specification of exogeneity. To be able to make comparisons with previous studies in the literature, we also conducted G...

This paper investigates the factors that affect the covariance between the federal funds rate and stock returns. I estimate a VAR system and implement covariance decomposition analysis. Most of the covariance between the federal funds rate and stock returns is affected by changes in stock market and output. These results conclude that the Fed is ac...

There are numerous empirical and theoretical studies that show that stock returns are affected by implementations of monetary policy. But, as mentioned in Bernanke and Kuttner (2005), very few studies tackle the question of why the stock market reacts to monetary policy. Romer and Romer (2000) and Sims (2002) show empirically that the Fed has super...

In the latest era, the significant usage of E-Procurement systems by governments and enterprises led to significant savings in government procurement costs. It has been shown theoretically and empirically that these savings are mostly caused by increased competitive environment, thus by increased number of bidders in government procurement auctions...

This paper theoretically investigates the optimal monetary policy regime for post-war Iraq. We analyze the macroeconomic dynamics (inflation, output and exchange rate) and the credibility and reputation of the Central Bank of Iraq (CBI) under alternative monetary policy regimes. We construct a detailed and realistic model that can be used to analyz...

This paper is the rst study that investigates eects of dollarization on the macroeconomic performance of Ecuador using a time series perspective. More specically, we investigate how dollarization eects ination, GDP, ination uncertainty and money-price relationship. There are four main ndings of this study. First, ination is lower after dollarizatio...

In the latest era, the significant increase in technology adoption enhanced the online procurement process. In this study, the factors affecting the usage and perceived acceptance of e-procurement have been studied. The relationship between cultural properties of the countries and e-Commerce activities of enterprises are found to be significant. Th...

E-commerce has been a widely used mean to purchase goods and services all over the world. This study investigates the role of cultural differences and information technology infrastructure on usage of e-commerce in developed and developing countries. As shown in Genis-Gruber and Tas (2007) cultural differences are expected to play a major role on e...

This paper empirically analyzes the effect of monetary policy changes on loan supply of Turkish banks and presents the evidence that bank lending channel of monetary policy transmission mechanism is operating through the capital adequacy of Turkish banks. By using the CAR as an indicator of capital constraint we show that banks that do not have cap...

One of the main characteristics of the peer-to-peer systems is the highly dynamic nature of the users present in the system. In such a rapidly changing enviroment, end-user guarantees become hard to handle. In this paper, we propose a search-theoretic view for performing lookups. We define a new search mechanism with cost-analysis for refining the...

This paper analyses the effects of the private information that the Fed has about current and future inflation on the predictability of stock returns. The results of long-horizon regressions conclude that Fed's inflation forecasts can be used to predict long and short term stock returns. The contamporenous regressions show that Fed's private inform...

It is known that stock returns are affected by monetary policy. This paper theoretically and empirically investigates whether asymmetric information between the Federal Reserve and the public causes the relation between stock returns and monetary policy actions. The paper concludes that asymmetric information between the Federal Reserve and the pub...

Working Papers are published without a formal refereeing process, with the sole purpose of generating discussion and feedback. Abstract This paper theoretically investigates the underlying mechanism behind the success of ination targeting (IT). We construct and solve a model of asymmetric information and learning between the Central Bank (CB) and p...

Starting from 2013, the monetary policy of the GCC countries will be governed by a single central bank. Examination of optimal monetary policy in these countries requires the analysis of the differences in monetary dynamics among these countries. This paper investigates the money-price relationship in GCC countries. The paper contributes to the lit...

E-commerce has been a widely used mean to purchase goods and services all over the world. This study investigates the role of cultural differences on usage of e-commerce. Using Hofstede's Uncertainty Avoidance Index (UAI) and Individualism Index (IND) to classify the countries and make the cultural comparisons among eight EU member countries, we em...