Characteristics of the Korean stock market correlations

In this study, we establish a network structure of the Korean stock market, one of the emerging markets, with its minimum spanning tree through the correlation matrix. Base on this analysis, it is found that the Korean stock market doesn't form the clusters of the business sectors or of the industry categories. When the MSCI (Morgan Stanley Capital International Inc.) index is exploited, we found that the clusters of the Korean stock market is formed. This finding implicates that the Korean market, in this context, is characteristically different form the mature markets.Comment: 11 pages, 3 figures, revised on June 200

The effect of a market factor on information flow between stocks using minimal spanning tree

We empirically investigated the effects of market factors on the information flow created from N(N-1)/2 linkage relationships among stocks. We also examined the possibility of employing the minimal spanning tree (MST) method, which is capable of reducing the number of links to N-1. We determined that market factors carry important information value regarding information flow among stocks. Moreover, the information flow among stocks evidenced time-varying properties according to the changes in market status. In particular, we noted that the information flow increased dramatically during periods of market crises. Finally, we confirmed, via the MST method, that the information flow among stocks could be assessed effectively with the reduced linkage relationships among all links between stocks from the perspective of the overall market

Effect of changing data size on eigenvalues in the Korean and Japanese stock markets

In this study, we attempted to determine how eigenvalues change, according to random matrix theory (RMT), in stock market data as the number of stocks comprising the correlation matrix changes. Specifically, we tested for changes in the eigenvalue properties as a function of the number and type of stocks in the correlation matrix. We determined that the value of the eigenvalue increases in proportion with the number of stocks. Furthermore, we noted that the largest eigenvalue maintains its identical properties, regardless of the number and type, whereas other eigenvalues evidence different features

Financial market contagion in the Asian crisis

This paper tests for evidence of contagion between the financial markets of Thailand, Malaysia, Indonesia, Korea, and the Philippines. Cross-country correlations among currencies and sovereign spreads are found to increase significantly during the crisis period, whereas the equity market correlations offer mixed evidence. A set of dummy variables using daily news is constructed to capture the impact of own-country and cross-border news on the markets. After controlling for own-country news and other fundamentals, the paper shows evidence of cross-border contagion in the currency and equity markets.

Do firms engage in earnings management to improve credit ratings?: Evidence from KRX bond issuers

In this paper, we examine the relationship between credit ratings, credit ratings changes and earnings management. Since the 1997 Asian Financial Crisis, many listed firms collapsed, leading investors to suffer losses. As a result, credit ratings have become a very important indicators of firms’ financial stability for investors, government agencies and debt issuers and other stakeholders. Firms with a similar credit rating are grouped together as firms of similar credit quality (Kisgen 2006) because credit ratings provide an ‘economically meaningful role’ (Boot et al. 2006). Numerous studies find that managers care deeply about their credit ratings (Graham and Harvey 2001; Kisgen 2009; Hovakimian at al. 2009). Firms that borrow equity in the form of bonds may have incentives to increase credit ratings with opportunistic earnings management. A change in a firm’s credit ratings has a direct impact on a firm’s profitability. Firm’s benefit from better terms from suppliers, enjoy better investment opportunities and have lower cost of capital when their credit risk is lower. Firms incur a higher cost of debt and experience additional costs when their credit risk is higher. American studies find that firms use earnings management to influence credit ratings (Ali and Zhang 2008; Jung et al. 2013; Alissa et al 2013). Credit rating agencies have stated they assume financial statements to be reasonable and accurate (Securities and Exchange Commission, 2003; Standard and Poor’s, 2006) and they do not consider themselves to be auditors. They take the information in the financial statements as accurate. Therefore, there is a potential for managers to engage in earnings management to influence credit ratings. In South Korea, there have been numerous experiments with auditor legislation because of financial collapses due to earnings management in the 2000s. Therefore, a decomposition of the relation between opportunistic earnings management and credit ratings is an important consideration for Korean accounting academia. Previous Korean studies have examined whether credit ratings in period t are significantly related to level of earnings management in the same period; however, those studies fail to find the consistent results. It is widely known that credit rating agencies allow one year credit watch period to assess default risk before credit rating decision. Firms with an incentive to increase their credit ratings through earnings management will only realize if earnings management positively influences credit ratings in the following year. Therefore, we focus on establishing a relationship between the levels of earnings management at time t and credit ratings / changes at time t+1. Our study provides a more robust analysis by establishing if both accrual based and real earnings management in period t influences credit ratings and credit rating changes in period t+1. Using a sample of 1,717 Korean KRX firm-years from 2002 to 2013, we find a negative relation between earnings management in period t and credit ratings in period t+1, suggesting that firms with higher credit ratings have lower levels of earnings management. Moreover, we find that firms that experience a credit ratings change in period t+1 are less likely to engage in opportunistic earnings management in period t, suggesting that firms do not have the potential to increase credit ratings. We also find that firms that experience a credit rating increase in period t+1 have a negative association with opportunistic earnings management for accruals measures. Moreover, when we split our sample into firms that experience 1) a credit rating increase, 2) decrease and 3) remaining the same, we find that firms that engage in earnings management are more likely to remain unchanged or experience a credit rating decrease. Thus, taken together, we find no evidence of relationship between opportunistic earnings management and an increase in credit ratings in the South Korean public debt market. Our results may be of interest to regulators, credit rating agencies, market participants and firms that question whether level of earnings management in current year influences credit ratings in the subsequent period

Community analysis of global financial markets

We analyze the daily returns of stock market indices and currencies of 56 countries over the period of 2002–2012. We build a network model consisting of two layers, one being the stock market indices and the other the foreign exchange markets. Synchronous and lagged correlations are used as measures of connectivity and causality among different parts of the global economic system for two different time intervals: non-crisis (2002–2006) and crisis (2007–2012) periods. We study community formations within the network to understand the influences and vulnerabilities of specific countries or groups of countries. We observe different behavior of the cross correlations and communities for crisis vs. non-crisis periods. For example, the overall correlation of stock markets increases during crisis while the overall correlation in the foreign exchange market and the correlation between stock and foreign exchange markets decrease, which leads to different community structures. We observe that the euro, while being central during the relatively calm period, loses its dominant role during crisis. Furthermore we discover that the troubled Eurozone countries, Portugal, Italy, Greece and Spain, form their own cluster during the crisis period.Published versio

Big Fish in Small Ponds: The Trading Behaviour and Price Impact of Foreign Investors in Asian Emerging Equity Markets

This paper analyses data for the aggregate daily trading of all foreign investors in six Asian emerging equity markets and provides two new findings. First, foreigners’ flows into several markets show positive-feedback trading with respect to global, as well as domestic, equity returns. In particular, foreigners tend to be buyers in these markets on the day after rises in these markets or in US markets. The nature of this trading suggests it is due to behavioural factors or foreigners extracting information from recent returns, rather than portfolio-rebalancing effects. Second, the price impacts associated with foreigners’ trading are much larger than earlier estimates. The results suggest that foreign investors and external conditions have a larger effect on emerging markets than implied by previous work.equity markets; emerging markets; foreign investors; positive-feedback trading; price impacts