03 Apr 2017
WHAT’S THE INVESTMENT ISSUE?
Investors have a limited amount of attention to give to their investment decisions. Many believe that paying attention to rankings of stocks provides them with a less attention demanding decision making shortcut. In reality, however, does paying attention to stocks ranked in a more salient place help improve financial decisions and market efficiency? Existing research on ranking and attention typically encounters the difficulty of separating out the pure effect of attention from that of fundamental news, which is especially true when rankings correlate with fundamentals. Thus, findings based on fundamental based rankings are subject to the confounding effects of both attention and fundamentals. The author tackles this challenge by exploring the price limit rule in China’s stock markets. Under that rule, stocks that hit the 10% upper price limit on a day are ranked by their daily returns, whose differentials are produced by mechanical rounding of maximum price changes as opposed to differential fundamental news. Investment practitioners in markets with the price limit rule in place may wish to exploit the impact of stock rankings for those stocks hitting the upper price limit. Thus, relevant questions to practitioners would pertain to (1) whether hitting the 10% upper price limit is truly an attention-grabbing event; (2) whether differential attention is allocated across the stocks hitting the price limit based on their rankings; and (3) whether stocks hitting the price limit that are ranked differently exhibit different subsequent returns, trading volume, volatility, and liquidity.
HOW DOES THE AUTHOR TACKLE THIS ISSUE?
The author conducted a series of tests to address the empirical questions posed above, studying a sample of China’s A-shares (shares that are quoted and traded in Chinese RMB) on China’s Shanghai Stock Exchange (SSE) and Shenzhen Stock Exchange (SZSE). The time period is from 16 December 1996, when SSE and SZSE initially established the current price limit rule, to 31 March 2015, when the research project was initiated. The author selects 2,505 out of 4,910 trading days; during these days the markets had at least 5 upper price-limit events. We hereafter call stocks that hit the upper price limit on a day the “event” stocks. For most stocks, the daily absolute price movement is regulated to be 10% of the previous trading day’s closing price. When the 10% price change is not an integer number of cents, the daily price limit is rounded to the nearest cent. This creates different maximum returns allowed across stocks with different previous closing prices. For example, stocks with the previous closing price of RMB 9.99, RMB 10.00, and RMB 10.01 would all have a daily maximum price change of RMB 1.00; this results in a maximum return limit of 10.01%, 10.00%, and 9.99%, respectively. The differential maximum return limit is, therefore, caused by mechanical rounding and not by differential fundamental news. As a result, the author identifies the pure effect of ranking by exploring the differential attention paid to the more saliently ranked stock, which returns 10.01% in a day in the previous example, versus those with less salient rankings, which return 10% or 9.99%, and the implications of rankings for the financial market. To carry out the tests, the author hand collected the website viewer data from hexun.com, one of the largest financial websites in China. The number of viewers from different IP addresses measures the attention paid by investors to a particular stock on a day. The author tested the impact of investor ranking by comparing two groups of event stocks, based on whether their event-day return was above median (usually 10%) or not, across dimensions of contemporaneous and subsequent returns, volume, volatility, and liquidity. Event stocks with the above median return were assigned to the high-rank group (with an average of above 12 stocks per day); the remainder were assigned to the low-rank group (with an average of near 10 stocks per day).
WHAT ARE THE FINDINGS?
The author finds that investors do pay significantly more attention to stocks hitting the price limit for several days on and after they hit the upper limit, measuring attention by the number of viewers on the hexun.com webpage. The abnormally high attention persists for two weeks after the event day. Furthermore, the high-rank group receives even more attention than the low-rank group on the event day and the subsequent three days. Relative to the low-rank group, the high-rank group of event stocks experiences a greater price increase for two days as well as a greater price reversal that follows within one to two weeks. As for trading volume, liquidity, and return volatility, the results suggest that during the post-event period, the high-attention group of event stocks exhibits higher trading volume, better liquidity, and higher volatility. Smaller investors are more affected by the rank effect. Moreover, the effect of trading volume and volatility is larger and persists longer, but the effect of liquidity is smaller and lasts only for a few days. These effects are noticeably stronger when a larger number of stocks are hitting the upper price limit on a particular day—thus, investors are more attention constrained and top rankings are more salient. The author conducts similar analyses on stocks with a 5% price limit and stocks that hit the 10% lower price limit. The evidence is overall weak, suggesting that it is the rankings of stocks that hit the upper price limit that matter most for attention allocation. When the maximum return is not extreme enough to make the top ranking, or the ranking is for losers and mainly attracts sellers, neither strong investor attention nor the effect of attention is found.
WHAT ARE THE IMPLICATIONS FOR INVESTORS AND INVESTMENT PROFESSIONALS?
The findings send a clear message that even pure rankings that are uncorrelated with fundamentals dictate investor attention and lead to large and predictable effects on asset prices. Understanding how ranking affects asset prices will help to improve portfolio performance for institutional and individual investors who trade in securities markets where financial assets are presented in various ranking formats. Investors may consider exploring the temporary price momentum and subsequent price reversal of highly ranked stocks, and more importantly, exploring the return differential between high- and low-rank groups of stocks using a long-short portfolio. The conventional wisdom is that having investors who pay attention is a good thing; it means that important fundamental news is received and consumed, leading to more efficient asset prices. Advances in behavioural finance in recent years, however, suggest that attention may have a detrimental effect when it interplays with behavioural biases, such as the pure order effect. The findings of this article demonstrate such evidence as well as opportunities for smart investors who are paying attention in the right places. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Summarized by Danling Jiang and Jingyu Cui. Danling Jiang is an Associate Professor of Finance at Stony Brook University—SUNY and the Chang Jiang Scholar Visiting Professor at Southwest Jiaotong University. Jingyu Cui is a Master of Science in Finance student at Stony Brook University—SUNY.