Online news-based stock price forecasting considering homogeneity in the industrial sector

Since stock movements forecasting is an important issue both academically and practically, studies related to stock price prediction have been actively conducted. The stock price forecasting research is classified into structured data and unstructured data, and it is divided into technical analysis, fundamental analysis and media effect analysis in detail. In the big data era, research on stock price prediction combining big data is actively underway. Based on a large number of data, stock prediction research mainly focuses on machine learning techniques. Especially, research methods that combine the effects of media are attracting attention recently, among which researches that analyze online news and utilize online news to forecast stock prices are becoming main. Previous studies predicting stock prices through online news are mostly sentiment analysis of news, making different corpus for each company, and making a dictionary that predicts stock prices by recording responses according to the past stock price. Therefore, existing studies have examined the impact of online news on individual companies. For example, stock movements of Samsung Electronics are predicted with only online news of Samsung Electronics. In addition, a method of considering influences among highly relevant companies has also been studied recently. For example, stock movements of Samsung Electronics are predicted with news of Samsung Electronics and a highly related company like LG Electronics.These previous studies examine the effects of news of industrial sector with homogeneity on the individual company. In the previous studies, homogeneous industries are classified according to the Global Industrial Classification Standard. In other words, the existing studies were analyzed under the assumption that industries divided into Global Industrial Classification Standard have homogeneity. However, existing studies have limitations in that they do not take into account influential companies with high relevance or reflect the existence of heterogeneity within the same Global Industrial Classification Standard sectors. As a result of our examining the various sectors, it can be seen that there are sectors that show the industrial sectors are not a homogeneous group. To overcome these limitations of existing studies that do not reflect heterogeneity, our study suggests a methodology that reflects the heterogeneous effects of the industrial sector that affect the stock price by applying k-means clustering. Multiple Kernel Learning is mainly used to integrate data with various characteristics. Multiple Kernel Learning has several kernels, each of which receives and predicts different data. To incorporate effects of target firm and its relevant firms simultaneously, we used Multiple Kernel Learning. Each kernel was assigned to predict stock prices with variables of financial news of the industrial group divided by the target firm, K-means cluster analysis. In order to prove that the suggested methodology is appropriate, experiments were conducted through three years of online news and stock prices. The results of this study are as follows. (1) We confirmed that the information of the industrial sectors related to target company also contains meaningful information to predict stock movements of target company and confirmed that machine learning algorithm has better predictive power when considering the news of the relevant companies and target company's news together. (2) It is important to predict stock movements with varying number of clusters according to the level of homogeneity in the industrial sector. In other words, when stock prices are homogeneous in industrial sectors, it is important to use relational effect at the level of industry group without analyzing clusters or to use it in small number of clusters. When the stock price is heterogeneous in industry group, it is important to cluster them into groups. This study has a contribution that we testified firms classified as Global Industrial Classification Standard have heterogeneity and suggested it is necessary to define the relevance through machine learning and statistical analysis methodology rather than simply defining it in the Global Industrial Classification Standard. It has also contribution that we proved the efficiency of the prediction model reflecting heterogeneity.

산업군 내 동질성을 고려한 온라인 뉴스 기반 주가예측

주가 예측은 학문적으로나 실용적으로나 중요한 문제이기에, 주가 예측에 관련된 연구가 활발히 진행되었다. 빅 데이터 시대에 도입하면서, 빅 데이터를 결합한 주가 예측 연구도 활발히 진행되고 있다. 다수의 데이터를 기반으로 기계 학습을 이용한 연구가 주를 이룬다. 특히 언론의 효과를 접목한 연구 방법들이 주목을 받고 있는데, 그중 온라인 뉴스를 분석하여 주가 예측에 활용하는 연구가 주를 이루고 있다. 기존 연구들은 온라인 뉴스가 개별 회사에 대한 미치는 영향을 주로 살펴보았다. 또한, 관련성이 높은 기업끼리 서로 영향을 주는 것을 고려하는 방법도 최근에 연구되고 있다. 이는 동질성을 가지는 산업군에 대한 효과를 살펴본 것인데, 기존 연구에서 동질성을 가지는 산업군은 국제 산업 분류 표준에 따른다. 즉, 기존 연구들은 국제 산업 분류 표준으로 나뉜 산업군이 동질성을 가진다는 가정하에서 분석을 시행하였다. 하지만 기존 연구들은 영향력을 가지는 회사를 고려하지 못한 채 예측하였거나 산업군 내에서 이질성이 존재하는 점을 반영하지 못했다는 한계점을 가진다. 본 연구는 산업군 내에 이질성이 존재함을 밝히고, 이질성을 반영하지 못한 기존 연구의 한계점을 K-평균 군집 분석을 적용하여, 주가에 영향을 미치는 산업군의 동질적인 효과를 반영할 수 있는 방법론을 제안하였다. 방법론이 적합하다는 것을 증명하기 위해 3년간의 온라인 뉴스와 주가를 통해 실험한 결과, 다수의 경우에서 본 논문에서 제시한 방법이 좋은 결과를 나타냄을 확인할 수 있었으며, 국제 산업 분류 표준 산업군 내에서 이질성이 클수록 본 논문에서 제시한 방법이 좋은 효과를 보인다는 것을 확인할 수 있었다. 본 연구는 국제 산업 분류 표준으로 나누어진 기업들이 높은 동질성을 가지지 않는 다는것을 밝히고 이를 반영한 예측 모형의 효율성을 입증하였다는 점에서 의의를 가진다.