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2.
PLoS One ; 18(11): e0294460, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38011183

RESUMO

The prediction of stock prices has long been a captivating subject in academic research. This study aims to forecast the prices of prominent stocks in five key industries of the Chinese A-share market by leveraging the synergistic power of deep learning techniques and investor sentiment analysis. To achieve this, a sentiment multi-classification dataset is for the first time constructed for China's stock market, based on four types of sentiments in modern psychology. The significant heterogeneity of sentiment changes in the sectors' leading stock markets is trained and mined using the Bi-LSTM-ATT model. The impact of multi-classification investor sentiment on stock price prediction was analyzed using the CNN-Bi-LSTM-ATT model. It finds that integrating sentiment indicators into the prediction of industry leading stock prices can enhance the accuracy of the model. Drawing upon four fundamental sentiment types derived from modern psychology, our dataset provides a comprehensive framework for analyzing investor sentiment and its impact on forecasting the stock prices of China's A-share market.


Assuntos
Comércio , Aprendizado Profundo , Indústrias , Investimentos em Saúde , Humanos , Povo Asiático , Atitude , China , Indústrias/economia , Indústrias/tendências , Modelos Econômicos , Investimentos em Saúde/tendências , Comércio/tendências , Previsões
3.
PLoS One ; 17(2): e0259869, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35180208

RESUMO

The purpose of our study is to figure out the transitions of the cryptocurrency market due to the outbreak of COVID-19 through network analysis, and we studied the complexity of the market from different perspectives. To construct a cryptocurrency network, we first apply a mutual information method to the daily log return values of 102 digital currencies from January 1, 2019, to December 31, 2020, and also apply a correlation coefficient method for comparison. Based on these two methods, we construct networks by applying the minimum spanning tree and the planar maximally filtered graph. Furthermore, we study the statistical and topological properties of these networks. Numerical results demonstrate that the degree distribution follows the power-law and the graphs after the COVID-19 outbreak have noticeable differences in network measurements compared to before. Moreover, the results of graphs constructed by each method are different in topological and statistical properties and the network's behavior. In particular, during the post-COVID-19 period, it can be seen that Ethereum and Qtum are the most influential cryptocurrencies in both methods. Our results provide insight and expectations for investors in terms of sharing information about cryptocurrencies amid the uncertainty posed by the COVID-19 pandemic.


Assuntos
COVID-19/epidemiologia , Investimentos em Saúde/tendências , Modelos Econômicos , COVID-19/economia , Humanos , Disseminação de Informação , Investimentos em Saúde/estatística & dados numéricos , Pandemias/economia , Incerteza
5.
PLoS One ; 16(11): e0260040, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34793525

RESUMO

Share pledging has become popular as a method of loan collateral among Chinese shareholders. Our research used a sample of Chinese listed firms between 2008-2018 and produced two main findings. Firstly, we found a negative association between stock price risk and firm profitability. Our second finding was that the interaction effect of share pledging and stock price risk is greater on firm profitability than the effect of stock price risk itself. We examined the role of share pledging by modeling pooled OLS and fixed effects using share pledging behavior, controlling shareholders' share pledging and the share pledging ratio to reinforce the robustness of our results. Furthermore, we investigated the Davis Double Play effect of share pledging to analyze how share pledging affects stock price risk. We found that higher EPS and investor expectations cannot mitigate the positive impact of share pledging on stock price risk. That is, the reduction of EPS and the deterioration of investor expectations caused by share pledging risk will not further aggravate the stock price risk, as shareholders may have taken some managerial actions to affect the transmission mechanism.


Assuntos
Comércio/tendências , Investimentos em Saúde/economia , Investimentos em Saúde/tendências , Povo Asiático/psicologia , China , Financiamento Pessoal/tendências , Humanos , Modelos Econômicos , Medição de Risco/economia
7.
Proc Natl Acad Sci U S A ; 118(36)2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34475206

RESUMO

We document a memory-based mechanism associated with investor overconfidence. In Studies 1 and 2, investors were asked to recall their most important trades in the recent past and then reported investing confidence and trading frequency. After the study, they looked up and reported the actual returns of these trades. In both studies, investors were biased to recall returns as higher than achieved, and larger memory biases were associated with greater overconfidence and trading frequency. The design of Study 2 allowed us to separately investigate the effects of two types of memory biases: distortion and selective forgetting. Both types of bias were present and were independently associated with overconfidence and trading frequency. Study 3 was an incentive-compatible experiment in which overconfidence and trading frequency were reduced when participants looked up previous consequential trades compared to when they reported them from memory.


Assuntos
Investimentos em Saúde/tendências , Memória/fisiologia , Variações Dependentes do Observador , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Autoimagem , Estados Unidos
8.
PLoS One ; 16(9): e0255038, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34555026

RESUMO

We present an experimental protocol to examine the relationship between exogenously induced stress and confidence in a setting applicable to financial markets. Confidence will be measured by a prediction interval for a one period ahead price forecast, based on a series of 100 previous prices; narrower (wider) prediction intervals will be indicative of greater (lower) confidence. Stress will be induced using the Cold Pressor Arm Wrap, a variation of the Cold Pressor Test. Risk attitudes, and personality traits are also considered as mediating factors.


Assuntos
Antecipação Psicológica , Braço/fisiopatologia , Comércio/economia , Previsões , Investimentos em Saúde/tendências , Estresse Fisiológico , Temperatura Baixa , Humanos , Investimentos em Saúde/economia
9.
PLoS One ; 16(7): e0253624, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34288930

RESUMO

BACKGROUND: Revelations that some members of Congress, including members of key health care committees, hold substantial personal investments in the health care industry have raised concerns about lawmakers' financial conflicts of interest (COI) and their potential impact on health care legislation and oversight. AIMS: 1) To assess historical trends in both the number of legislators holding health care-related assets and the value and composition of those assets. 2) To compare the financial holdings of members of health care-focused committees and subcommittees to those of other members of the House and Senate. METHODS: We analyzed 11 years of personal financial disclosures by all members of the House and Senate. For each year, we calculated the percentage of members holding a health care-related asset (overall, by party, and by committee); the total value of all assets and health care-related assets held; the mean and median values of assets held per member; and the share of asset values attributable to 9 health asset categories. FINDINGS: During the study period, over a third of all members of Congress held health care-related assets. These assets were often substantial, with a median total value per member of over $43,000. Members of health care-focused committees and subcommittees in the House and Senate did not hold health care-related assets at a higher rate than other members of their respective chambers. CONCLUSIONS: These findings suggest that lawmakers' health care-related COI warrant the same level of attention that has been paid to the COI of other actors in the health care system.


Assuntos
Atenção à Saúde/economia , Governo Federal , Empregados do Governo/estatística & dados numéricos , Investimentos em Saúde/tendências , Conflito de Interesses , Revelação , Humanos , Investimentos em Saúde/economia , Investimentos em Saúde/estatística & dados numéricos , Política , Estados Unidos
10.
PLoS One ; 16(6): e0253121, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34161352

RESUMO

Stock price prediction has long been the subject of research because of the importance of accuracy of prediction and the difficulty in forecasting. Traditionally, forecasting has involved linear models such as AR and MR or nonlinear models such as ANNs using standardized numerical data such as corporate financial data and stock price data. Due to the difficulty of securing a sufficient variety of data, researchers have recently begun using convolutional neural networks (CNNs) with stock price graph images only. However, we know little about which characteristics of stock charts affect the accuracy of predictions and to what extent. The purpose of this study is to analyze the effects of stock chart characteristics on stock price prediction via CNNs. To this end, we define the image characteristics of stock charts and identify significant differences in prediction performance for each characteristic. The results reveal that the accuracy of prediction is improved by utilizing solid lines, color, and a single image without axis marks. Based on these findings, we describe the implications of making predictions only with images, which are unstructured data, without using large amounts of standardized data. Finally, we identify issues for future research.


Assuntos
Algoritmos , Comércio/economia , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Investimentos em Saúde/economia , Modelos Econômicos , Redes Neurais de Computação , Comércio/tendências , Previsões , Humanos , Investimentos em Saúde/tendências , Probabilidade
11.
PLoS One ; 16(5): e0250846, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34014976

RESUMO

We explore the use of implied volatility indices as a tool for estimate changes in the synchronization of stock markets. Specifically, we assess the implied stock market's volatility indices' predictive power on synchronizing global equity indices returns. We built the correlation network of 26 stock indices and implemented in-sample and out-of-sample tests to evaluate the predictive power of VIX, VSTOXX, and VXJ implied volatility indices. To measure markets' synchronization, we use the Minimum Spanning Tree length and the length of the Planar Maximally Filtered Graph. Our results indicate a high predictive power of all the volatility indices, both individually and together, though the VIX predominates over the evaluated options. We find that an increase in the markets' volatility expectations, captured by the implied volatility indices, is a good Granger predictor of an increase in the synchronization of returns in the following month. Estimating, monitoring, and predicting returns' synchronization is essential for investment decision-making, especially for diversification strategies and regulating financial systems.


Assuntos
Previsões/métodos , Investimentos em Saúde/tendências , Humanos , Investimentos em Saúde/economia , Modelos Econômicos
12.
Drug Discov Today ; 26(8): 1784-1789, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34022459

RESUMO

Comparative analysis of the R&D efficiency of 14 leading pharmaceutical companies for the years 1999-2018 shows that there is a close positive correlation between R&D spending and the two investigated R&D output parameters, approved NMEs and the cumulative impact factor of their publications. In other words, higher R&D investments (input) were associated with higher R&D output. Second, our analyses indicate that there are 'economies of scale' (size) in pharmaceutical R&D.


Assuntos
Desenvolvimento de Medicamentos/tendências , Indústria Farmacêutica/tendências , Pesquisa/tendências , Desenvolvimento de Medicamentos/economia , Desenvolvimento de Medicamentos/estatística & dados numéricos , Indústria Farmacêutica/economia , Indústria Farmacêutica/estatística & dados numéricos , Humanos , Investimentos em Saúde/economia , Investimentos em Saúde/estatística & dados numéricos , Investimentos em Saúde/tendências , Preparações Farmacêuticas/administração & dosagem , Pesquisa/economia , Pesquisa/estatística & dados numéricos
13.
Proc Natl Acad Sci U S A ; 118(4)2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33468667

RESUMO

We analyze how investor expectations about economic growth and stock returns changed during the February-March 2020 stock market crash induced by the COVID-19 pandemic, as well as during the subsequent partial stock market recovery. We surveyed retail investors who are clients of Vanguard at three points in time: 1) on February 11-12, around the all-time stock market high, 2) on March 11-12, after the stock market had collapsed by over 20%, and 3) on April 16-17, after the market had rallied 25% from its lowest point. Following the crash, the average investor turned more pessimistic about the short-run performance of both the stock market and the real economy. Investors also perceived higher probabilities of both further extreme stock market declines and large declines in short-run real economic activity. In contrast, investor expectations about long-run (10-y) economic and stock market outcomes remained largely unchanged, and, if anything, improved. Disagreement among investors about economic and stock market outcomes also increased substantially following the stock market crash, with the disagreement persisting through the partial market recovery. Those respondents who were the most optimistic in February saw the largest decline in expectations and sold the most equity. Those respondents who were the most pessimistic in February largely left their portfolios unchanged during and after the crash.


Assuntos
COVID-19/economia , COVID-19/psicologia , Investimentos em Saúde/economia , Pandemias/economia , COVID-19/epidemiologia , Desenvolvimento Econômico , Humanos , Investimentos em Saúde/tendências , Marketing/economia , Modelos Econômicos , SARS-CoV-2/isolamento & purificação , Inquéritos e Questionários
16.
PLoS One ; 15(12): e0242449, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33259510

RESUMO

In this paper, two new aggregation operators based on Choquet integral, namely the induced generalized interval neutrosophic Choquet integral average operator(IGINCIA) and the induced generalized interval neutrosophic Choquet integral geometric operator(IG-INCIG), are proposed for multi-criteria decision making problems (MCDM). Firstly, the criteria are dependent to each other and the evaluation information of the criteria are expressed by interval neutrosophic numbers. Moreover, two indices which are inspired by the geometrical structure are established to compare the interval neutrosophic numbers. Then, a MCDM method is proposed based on the proposed aggregation operators and ranking indices to cope with MCDM with interactive criteria. Lastly, an investment decision making problem is provided to illustrate the practicality and effectiveness of the proposed approach. The validity and advantages of the proposed method are analyzed by comparing with some existing approaches. By a numerical example in company investment to expand business though five alternatives with considering four criteria, the optimal decision is made.


Assuntos
Tomada de Decisões , Técnicas de Apoio para a Decisão , Teoria da Decisão , Investimentos em Saúde/tendências , Algoritmos , Entropia , Lógica Fuzzy , Humanos
17.
PLoS One ; 15(12): e0244225, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33351834

RESUMO

ESG factors are becoming mainstream in portfolio investment strategies, attracting increasing fund inflows from investors who are aligning their investment values to Sustainable Development Goals (SDG) declared by the United Nations Principles for Responsible Investments. Do investors sacrifice return for pursuing ESG-aligned megatrend goals? The study analyses the risk-adjusted financial performance of ESG-themed megatrend investment strategies in global equity markets. The analysis covers nine themes for the period 2015-2019: environmental megatrends covering energy efficiency, food security, and water scarcity; social megatrends covering ageing, millennials, and urbanisation; governance megatrends covered by cybersecurity, disruptive technologies, and robotics. We construct megatrend factor portfolios based on signalling theory and formulate a novel measure for stock megatrend exposure (MTE), based on the relative fund flows into the corresponding thematic ETFs. We apply pure factor portfolios methodology based on constrained WLS cross-sectional regressions to calculate Fama-French factor returns. Time-series regression rests on the generalised method of moments estimator (GMM) that uses robust distance instruments. Our findings show that each environmental megatrend, as well as the disruptive technologies megatrend, yielded positive and significant alphas relative to the passive strategy, although this outperformance becomes statistically insignificant in the Fama-French 5-factor model context. The important result is that most of the megatrend factor portfolios yielded significant non-negative alphas; which supports our assumption that megatrend investing strategy promotes SDGs while not sacrificing returns, even when accounting for transaction costs up to 50bps/annum. Higher transaction costs, as is the case for some of these ETFs with expense ratios reaching 80-100bps, may be an indication of two things: ESG-themed megatrend investors were willing to sacrifice ca. 30-50bps of annual return to remain aligned with sustainability targets, or that expense ratio may well decline in the future.


Assuntos
Investimentos em Saúde/economia , Modelos Econômicos , Desenvolvimento Econômico , Investimentos em Saúde/normas , Investimentos em Saúde/tendências
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