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Compras públicas brasileiras: comércio eletrônico

Kovalski, Simão Luiz
Fonte: Instituto Universitário de Lisboa Publicador: Instituto Universitário de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2011 Português
Relevância na Pesquisa
37.889365%
Mestrado em Administração Pública; O Presente trabalho de dissertação contextualiza a evolução e as reformas da administração pública, passando pelos novos conceitos e modelos, como a New Public Management (Nova Gestão Pública), baseada nas orientações gestionárias das organizações privadas e o New Public Service (Nova Administração Pública), orientada nas transformações da gestão profissional e da organização institucional do modelo de administração Weberiano dos Estados democráticos europeus. Também são abordados os conceitos de Governança e Accountability, que reforçam as formas democráticas de relacionamento, entre o Estado e a sociedade, principalmente em países recém saídos de longos períodos de ditaduras, como o Brasil. Em seguida, contextualiza-se o Governo Eletrônico, passando pelas iniciativas que contribuíram para a origem da Sociedade da Informação; com destaque para as Tecnologias da Informação e Comunicação – TICs, nos avanços do governo e comércio eletrônicos. O foco do trabalho está na análise da legislação brasileira de compras públicas, no tocante a regulamentação do pregão eletrônico, cuja implantação permitiu, ao Governo Federal, criar um sistema de Comércio Eletrônico visando à realização de compras públicas. Por fim...

Web Search Queries Can Predict Stock Market Volumes

Bordino, Ilaria; Battiston, Stefano; Caldarelli, Guido; Cristelli, Matthieu; Ukkonen, Antti; Weber, Ingmar
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/07/2012 Português
Relevância na Pesquisa
37.842803%
We live in a computerized and networked society where many of our actions leave a digital trace and affect other people’s actions. This has lead to the emergence of a new data-driven research field: mathematical methods of computer science, statistical physics and sociometry provide insights on a wide range of disciplines ranging from social science to human mobility. A recent important discovery is that search engine traffic (i.e., the number of requests submitted by users to search engines on the www) can be used to track and, in some cases, to anticipate the dynamics of social phenomena. Successful examples include unemployment levels, car and home sales, and epidemics spreading. Few recent works applied this approach to stock prices and market sentiment. However, it remains unclear if trends in financial markets can be anticipated by the collective wisdom of on-line users on the web. Here we show that daily trading volumes of stocks traded in NASDAQ-100 are correlated with daily volumes of queries related to the same stocks. In particular, query volumes anticipate in many cases peaks of trading by one day or more. Our analysis is carried out on a unique dataset of queries, submitted to an important web search engine, which enable us to investigate also the user behavior. We show that the query volume dynamics emerges from the collective but seemingly uncoordinated activity of many users. These findings contribute to the debate on the identification of early warnings of financial systemic risk...

Transparency, Trade Costs, and Regional Integration in the Asia Pacific

Helble, Matthias; Shepherd, Ben; Wilson, John S.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
38.031487%
The authors show in this paper that increasing the transparency of the trading environment can be an important complement to traditional liberalization of tariff and non-tariff barriers. Our definition of transparency is grounded in a transaction cost analysis. The authors focus on two dimensions of transparency: predictability (reducing the cost of uncertainty) and simplification (reducing information costs). Using the Asia Pacific Economic Cooperation (APEC) member economies as a case study, the authors construct indices of importer and exporter transparency for the region from a wide range of sources. Our results from a gravity model suggest that improving trade-related transparency in APEC could hold significant benefits by raising intra-APEC trade by proximately USD 148 billion or 7.5 pecent of baseline trade in the region.

Rules of Origin for Preferential Trading Arrangements : Implications for the ASEAN Free Trade Area of EU and U.S. Experience

Cadot, Olivier; de Melo, Jaime; Portugal-Pérez, Alberto
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
37.860044%
With free trade areas (FTAs) under negotiation between Japan and the ASEAN Free Trade Area (AFTA) members and between the Republic of Korea and AFTA members, preferential market access will become more important in Asian regionalism. Protectionist pressures will likely increase through rules of origin, the natural outlet for these pressures. Based on the experience of the European Union and the United States with rules of origin, the authors argue that, should these FTAs follow in the footsteps of the EU and the U.S. and adopt similar rules of origin, trading partners in the region would incur unnecessary costs. Using EU trade under the Generalized System of Preferences with Africa, Caribbean, and Pacific partners, the authors estimate how the use of preferences would likely change if AFTA were to veer away from its current uniform rules of origin requiring a 40 percent local content rate. Depending on the sample used, a 10 percentage point reduction in the local value content requirement is estimated to increase the utilization rate of preferences by between 2.5 and 8.2 percentage points.

International Experience with Cross-border Power Trading

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Português
Relevância na Pesquisa
47.84057%
The five main lessons for Southern Africa from our review of the experiencewith cross-border power trading in other regions of the work are that: Security of supply concerns need to be explicitly addressed and understood by the parties to proposed cross-border transactions. Regional entities need to be empowered to make decisions based on legally enforceable national government commitments, particularly in relation to planning, pricing, and settlement rules. Bilateral trading provides a basis for expanding trading volumes, both through constructing the physical infrastructure that future deals will use and by establishing workable legal and regulatory frameworks. Power pools will help to generate sustained increases in cross-border trading along with other regional trading arrangements, particularly in power systems with several interconnection. The substance and process of regulatory reviews in importing and exporting countries must be clear to create sufficient investment certainty.

Uninformative announcements and asset trading behavior

Corgnet, Brice; Kujal, Praveen; Porter, Dave
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/workingPaper; info:eu-repo/semantics/workingPaper Formato: application/pdf
Publicado em /12/2007 Português
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37.971887%
Financial markets are overwhelmed by daily announcements. We use experimental asset markets to assess the impact of uninformative communications on asset prices and trading volumes. We deliver uninformative messages in standard experimental asset markets and find that trading volumes and prices are impacted by these messages. In particular, the release of a pre-announced preset message to traders “The price is too high” in predetermined trading periods decreases the amplitude and duration of bubbles. Also, the release of the messages “The price is too high” or “The price is too low” reduces trading volume with inexperienced subjects.

Risk, Return and Volume in an Emerging Stock Market: The Bilbao Stock Exchange, 1916-1936

Battilossi, Stefano; Houpt, Stefan
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/workingPaper; info:eu-repo/semantics/conferenceObject Formato: text/plain; application/pdf
Publicado em /06/2006 Português
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38.162573%
We constructed a unique data set including price and trade volumes for the Bilbao Stock Exchange (BSE) in the interwar period in order to calculate two alternative market indices (weighted and unweighted). The characteristics of the weekly returns on the market portfolio and trading volumes are analyzed in order to test the existence of various phenomena typical of emerging markets, such as autocorrelation and high persistence of volatility shocks, and other features of advanced markets, such as the risk-return relationship and the relationship between trading volumes and returns. The methodological approach is based on an augmented GARCH-cum-volume model. We find strong evidence in favour of autocorrelation and GARCH effects, no evidence of risk-return relationship, and weak evidence of a contemporaneous impact of trading volumes on returns. These findings are generally in line with the results obtained by recent studies on emerging markets.; Workshop Financial Centres as Competing Clusters, Paris School of Economics, January 30th, 2008

The role of information and trading volume on intradaily and weekly returns patterns in the Spanish stock market

Camino Blasco, David
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Trabalho em Andamento Formato: application/pdf
Publicado em /01/1996 Português
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47.860044%
The aim of this work is to document new results about intradaily and weekly effects in the Spanish stock market, relating the returns in the stock index, during trading and non trading hours, to the arrival of information and daily trading volume. Weekly and intraday patterns are examined using the index Ibex-35 transaction data. Twenty-three months oftransaction records of the Ibex-35, at 15-minutes intervals, were examined in an attempt to better understand the dayof-the week effect and trading return patterns, to further characterize systematic weekly and intradaily price patterns. Several results were found: -There are cross-sectional differences in weekday patterns found in both trading and nontrading period returns. These patterns are pervasive over time and for different trading volumes. We found a positive relation between opening volume and unexpected overnight volatility, which is reflected in a higher standard deviation of returns, during the first to first and half hours of trading. -There are significant weekday differences in intraday trading returns in the first four hours of trading. On Monday (and Wednesday) returns are negative, while on the other weekdays, returns in this interval, are positive.

Deregularization, insider trading and tender offers

Camino Blasco, David; López Gómez, Miguel Ángel
Fonte: SSRN Publicador: SSRN
Tipo: info:eu-repo/semantics/submittedVersion; info:eu-repo/semantics/workingPaper Formato: application/pdf
Publicado em /06/2002 Português
Relevância na Pesquisa
37.860044%
This paper examines insider trading operations and the transmission of information to markets, during the merger and firm acquisition process, that followed the deregulation and restructuring of the Spanish electrical sector, who began in 1993 and is still under way in many countries of the European Union (Green Paper, 2001). In particular, we will study the events surrounding the 1996 acquisition of FECSA and Sevillana de Electricidad, two of the Spanish biggest electricity suppliers and distributors, by ENDESA, a formerly state owned company and the nation’s largest power supplier We use public trading records around the announcement date of the event to track abnormal returns, market volumes and spreads and to isolate individual transaction records by broker, from the flow of background trading, permitting the analysis of the market ’s reaction to the onset of informed trading. Because the insider information was not revealed to other market participants until the event, and even rumors of the acquisition were publicly and officially denied, this case presents a unique laboratory for studying the dissemination and incorporation of private inside information into market prices. Unlike earlier studies that make use of daily transactions and concentrates on how informed trading affects stock prices...

Liquidez e rendibilidade das acções de empresas admitidas em bolsas estrangeiras

Febra, Lígia Catarina Marques
Fonte: Instituto Superior de Economia e Gestão Publicador: Instituto Superior de Economia e Gestão
Tipo: Tese de Doutorado
Publicado em /02/2010 Português
Relevância na Pesquisa
37.889365%
Doutoramento em Gestão; O presente estudo tem como objecto de investigação os efeitos da admissão à cotação de uma empresa numa bolsa estrangeira sobre a liquidez, e compreende a análise de três questões: impacto no volume de transacções; relação entre rendibilidade e liquidez; e impacto da fusão NYSE/Euronext na liquidez das acções de empresas admitidas num mercado estrangeiro. Os resultados indicam que as características das empresas e as caractrísticas do mercado doméstico e do mercado estrangeiro são determinantes para o sucesso de uma admissão num mercado estrangeiro no que respeita à liquidez. Em particular, verificamos que o impacto da admissão num mercado estranjeiro sobre a liquidez das acções de empresas de mercados domésticos emergentes é positivo em termos globais. Relativamente à questão da relação entre rendibilidade e liquidez, o estudo permite verificar que a liquidez, quer individual, quer sistemática, tem um papel relevante no comportamento da rendibilidade no período de 52 semanas antes e depois da admissão das acções num mercado estrangeiro. No que respeita ao último estudo, os resultados mostram que a fusão parece não ter um impacto, no curto prazo, sobre a liquidez das acções estrangeiras cotadas na Euronext e sobre as acções de empresas da Euronext com segunda cotação em NYSE. Por outro lado...

Asset pricing using trading volumes in a hidden regime-switching environment

Elliott, R.J.; Siu, T.K.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
Relevância na Pesquisa
68.315605%
By utilizing information about prices and trading volumes, we discuss the pricing of European contingent claims in a continuous-time hidden regime-switching environment. Hidden market sentiments described by the states of a continuous-time, finite-state, hidden Markov chain represent a common factor for an asset’s drift and volatility, as well as its trading volumes. Using observations about trading volumes, we present a filtered estimate of the hidden common factor. The asset pricing problem is then considered in a filtered market, where the hidden drift and volatility are replaced by their filtered estimates. We adopt the Esscher transform to select an equivalent martingale measure for pricing and derive a partial-differential integral equation for the option price.; Robert J. Elliot, Tak Kuen Siu

Short-term effects of analysts recommendations in spanish blue chips returns and trading volumes; Efectos a corto plazo de las recomendaciones de los analistas en las rentabilidades y volúmenes de negociación de las principales empresas españolas

Argilés Bosch, Josep María; García Blandón, Josep
Fonte: Universidad de Chile. Facultad de Economía y Negocios Publicador: Universidad de Chile. Facultad de Economía y Negocios
Tipo: Artículo de revista
Português
Relevância na Pesquisa
47.56959%
Artículo de publicación ISI; The purpose of this to investigate the effects of stock recommendations in returns and trading volumes. Unlike previous research we have investigated the five most usual types of recommendations: buy autperform, hold, underperform and sell.

Web search queries can predict stock market volumes

Bordino, Ilaria; Battiston, Stefano; Caldarelli, Guido; Cristelli, Matthieu; Ukkonen, Antti; Weber, Ingmar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.913308%
We live in a computerized and networked society where many of our actions leave a digital trace and affect other people's actions. This has lead to the emergence of a new data-driven research field: mathematical methods of computer science, statistical physics and sociometry provide insights on a wide range of disciplines ranging from social science to human mobility. A recent important discovery is that query volumes (i.e., the number of requests submitted by users to search engines on the www) can be used to track and, in some cases, to anticipate the dynamics of social phenomena. Successful exemples include unemployment levels, car and home sales, and epidemics spreading. Few recent works applied this approach to stock prices and market sentiment. However, it remains unclear if trends in financial markets can be anticipated by the collective wisdom of on-line users on the web. Here we show that trading volumes of stocks traded in NASDAQ-100 are correlated with the volumes of queries related to the same stocks. In particular, query volumes anticipate in many cases peaks of trading by one day or more. Our analysis is carried out on a unique dataset of queries, submitted to an important web search engine, which enable us to investigate also the user behavior. We show that the query volume dynamics emerges from the collective but seemingly uncoordinated activity of many users. These findings contribute to the debate on the identification of early warnings of financial systemic risk...

Modeling interaction of trading volume in financial dynamics

Ren, F.; Zheng, B.; Chen, P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
47.75366%
A dynamic herding model with interactions of trading volumes is introduced. At time $t$, an agent trades with a probability, which depends on the ratio of the total trading volume at time $t-1$ to its own trading volume at its last trade. The price return is determined by the volume imbalance and number of trades. The model successfully reproduces the power-law distributions of the trading volume, number of trades and price return, and their relations. Moreover, the generated time series are long-range correlated. We demonstrate that the results are rather robust, and do not depend on the particular form of the trading probability.; Comment: 7 pages, 4 figures

Analysis of trade packages in Chinese stock market

Ren, Fei; Zhou, Wei-Xing
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/03/2011 Português
Relevância na Pesquisa
38.245679%
This paper conducts an empirically study on the trade package composed of a sequence of consecutive purchases or sales of 23 stocks in Chinese stock market. We investigate the probability distributions of the execution time, the number of trades and the total trading volume of trade packages, and analyze the possible scaling relations between them. Quantitative differences are observed between the institutional and individual investors. The trading profile of trade packages is investigated to reveal the preference of large trades on trading volumes and transaction time of the day, and the different profiles of two types of investors imply that institutions may be more informed than individuals. We further analyze the price impacts of both the entire trade packages and the individual transactions inside trade packages. We find the price impact of trade packages is nonnegligible over the period of the execution time and it may have a power-law relation with the total trading volume. The price impact of the transactions inside trade packages displays a U-shaped profile with respect to the time $t$ of the day, and also shows a power-law dependence on their trading volumes. The trading volumes of the transactions inside trade packages made by institutions have a stronger impact on current returns...

Preferred numbers and the distribution of trade sizes and trading volumes in the Chinese stock market

Mu, Guo-Hua; Chen, Wei; Kertész, János; Zhou, Wei-Xing
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/12/2008 Português
Relevância na Pesquisa
48.23308%
The distribution of trade sizes and trading volumes are investigated based on the limit order book data of 22 liquid Chinese stocks listed on the Shenzhen Stock Exchange in the whole year 2003. We observe that the size distribution of trades for individual stocks exhibits jumps, which is caused by the number preference of traders when placing orders. We analyze the applicability of the "$q$-Gamma" function for fitting the distribution by the Cram\'{e}r-von Mises criterion. The empirical PDFs of trading volumes at different timescales $\Delta{t}$ ranging from 1 min to 240 min can be well modeled. The applicability of the $q$-Gamma functions for multiple trades is restricted to the transaction numbers $\Delta{n}\leqslant8$. We find that all the PDFs have power-law tails for large volumes. Using careful estimation of the average tail exponents $\alpha$ of the distribution of trade sizes and trading volumes, we get $\alpha>2$, well outside the L{\'e}vy regime.; Comment: 7 pages, 5 figures and 4 tables

Trading leads to scale-free self-organization

Ebert, M.; Paul, W.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/05/2009 Português
Relevância na Pesquisa
47.56648%
Financial markets display scale-free behavior in many different aspects. The power-law behavior of part of the distribution of individual wealth has been recognized by Pareto as early as the nineteenth century. Heavy-tailed and scale-free behavior of the distribution of returns of different financial assets have been confirmed in a series of works. The existence of a Pareto-like distribution of the wealth of market participants has been connected with the scale-free distribution of trading volumes and price-returns. The origin of the Pareto-like wealth distribution, however, remained obscure. Here we show that it is the process of trading itself that under two mild assumptions spontaneously leads to a self-organization of the market with a Pareto-like wealth distribution for the market participants and at the same time to a scale-free behavior of return fluctuations. These assumptions are (i) everybody trades proportional to his current capacity and (ii) supply and demand determine the relative value of the goods.

Recurrence interval analysis of trading volumes

Ren, Fei; Zhou, Wei-Xing
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/02/2010 Português
Relevância na Pesquisa
58.603438%
We study the statistical properties of the recurrence intervals $\tau$ between successive trading volumes exceeding a certain threshold $q$. The recurrence interval analysis is carried out for the 20 liquid Chinese stocks covering a period from January 2000 to May 2009, and two Chinese indices from January 2003 to April 2009. Similar to the recurrence interval distribution of the price returns, the tail of the recurrence interval distribution of the trading volumes follows a power-law scaling, and the results are verified by the goodness-of-fit tests using the Kolmogorov-Smirnov (KS) statistic, the weighted KS statistic and the Cram{\'{e}}r-von Mises criterion. The measurements of the conditional probability distribution and the detrended fluctuation function show that both short-term and long-term memory effects exist in the recurrence intervals between trading volumes. We further study the relationship between trading volumes and price returns based on the recurrence interval analysis method. It is found that large trading volumes are more likely to occur following large price returns, and the comovement between trading volumes and price returns is more pronounced for large trading volumes.; Comment: 9 pages, 9 figures and 1 table

Análise empírica da prática de insider trading em processos de fusões e aquisições recentes na economia brasileira; Empirical analysis of insider trading in recent brazilian mergers and acquisitions

Camargos, Marcos Antônio de; Romero, Julio Alfredo Racchumi; Barbosa, Francisco Vidal
Fonte: Universidade de São Paulo. Faculdade de Economia, Administração e Contabilidade Publicador: Universidade de São Paulo. Faculdade de Economia, Administração e Contabilidade
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/12/2008 Português
Relevância na Pesquisa
37.840571%
As negociações com uso de informações privilegiadas (insider trading) criam oportunidades para que alguns agentes do mercado lucrem em detrimento de outros, levando a uma transferência de riqueza entre os acionistas. O anúncio de uma fusão ou aquisição é um momento oportuno para essa prática, visto que quase sempre causa impactos significativos nas expectativas dos agentes do mercado e nos preços dos títulos. Este artigo analisou se essa prática esteve presente em processos de fusões e aquisições recentes, realizados por grandes empresas brasileiras, utilizando-se de um estudo de evento para o qual, além da análise do retorno acionário anormal, fez-se a comparação de médias de variáveis sinalizadoras do comportamento dos títulos no mercado (liquidez). Para a análise foram utilizadas ações preferenciais, ordinárias e os American Depositary Receipts (ADRs) de dez empresas diferentes. Foi encontrada evidência empírica da prática de insider trading no retorno acionário anormal e na quantidade de negociações, além de se observarem indícios dessa prática nas demais variáveis analisadas, o que sinaliza que ocorreu um aumento da liquidez dos títulos analisados antes do anúncio.; Insider trading creates opportunities for some agents in the market to profit in detriment of others thereby transferring wealth between shareholders. Announcement of a merger or acquisition is an opportunity for this practice as it usually causes significant price changes and impacts stock market expectations of these agents. An analysis was made to detect insider trading in recent mergers and acquisitions by large Brazilian companies...

Daily closing inside spreads and trading volumes around earnings announcements

Acker, Daniella; Stalker, Mathew; Tonks, Ian
Fonte: Financial Markets Group, London School of Economics and Political Science Publicador: Financial Markets Group, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /02/2002 Português
Relevância na Pesquisa
48.162573%
This paper examines the determinants of inside spreads and their behaviour around corporate earning announcement dates, for a sample of UK firms over the period 1986-94. The paper finds that closing daily inside spreads are affected by order processing costs (proxied by trading volumes), inventory control costs (trading volumes and return variability) and asymmetric information (unusually high trading volumes). Inside spreads start to narrow 15 days before an earnings announcement, and narrow further by the end of the announcement day. We also identify a puzzling phenomenon. There is only a ‘sluggish’ recovery of spreads after the announcement: inside spreads continue to remain at relatively narrow levels, and take up to 90 days to recover to their pre-announcement width.