S&P 500 trading strategies and stock betas

This paper shows that S&P 500 stock betas are overstatedand the non-S&P 500 stock betas are understated becauseof liquidity price effects caused by the S&P 500 tradingstrategies. The daily and weekly betas of stocks added to theS&P 500 index during 1985-1989 increase, on average, by0.211 and 0.130. The difference between monthly betas of otherwisesimilar S&P 500 and non-S&P 500 stocks also equals 0.125during this period. Some of these increases can be explainedby the reduced nonsynchroneity of S&P 500 stock prices,but the remaining increases are explained by the price pressureor excess volatility caused by the S&P 500 trading strategies.I estimate that the price pressures account for 8.5 percentof the total variance of daily returns of a value-weighted portfolioof NYSE/AMEX stocks. The negative own autocorrelations in S&P500 index returns and the negative cross autocorrelations betweenS&P 500 stock returns provide further evidence consistentwith the price pressure hypothesis.     

Option prices and stock market momentum: evidence from China

Option prices tend to be correlated to past stock market returns due to market imperfections. We unprecedentedly examine this issue on the SSE 50 ETF option in the Chinese derivatives market. To measure the price pressure in the options market, we construct an implied volatility spread based on pairs of the SSE 50 ETF option with identical expiration dates and strike prices. By regressing the implied volatility spread on past stock returns, we find that past stock returns exert a strong influence on the pricing of index options. Specifically, we find that SSE 50 ETF calls are significantly overvalued relative to SSE 50 ETF puts after stock price increases and the reverse is also true after the stock price decreases. Moreover, we validate the momentum effects in the underlying stock market to be responsible for the price pressure. These findings are both economically and statistically significant and have important implications.     

Predicting firm level stock returns: Implications for asset pricing and economic links

We examine the predictive ability of stock price ratios, stock return dispersion and distribution measures for firm level returns. Analysis typically focusses on market level returns, however, for the underlying asset pricing model to hold, firm-level predictability should be present. Additionally, we examine the economic content of predictability by considering whether the predictive coefficient has the theoretically correct sign and whether it is related to future output growth. While stock returns reflect investor expectations regarding future economic conditions, they are often too noisy to act as predictor. We use the time-varying predictive coefficient as it reflects investor confidence in the predictive relation. Results suggest that a subset of stock price ratios have predictive power for individual firm stock returns, exhibit the correct coefficient sign and has predictive power for output growth. Each of these ratios has a measure of fundamentals divided by the stock price and has a positive relation with stock returns and output growth. This implies that as investors expect future economic conditions to improve and earnings and dividends to rise, so expected stock returns will increase. This supports the cash flow channel as the avenue through which stock return predictability arises.     

The valuation effects of stock splits and stock dividends

This study presents evidence which indicates that stock prices, on average, react positively to stock dividend and stock split announcements that are uncontaminated by other contemporaneous firm-specific announcements. In addition, it documents significantly positive excess returns on and around the ex-dates of stock dividends and splits. Both announcement and ex-date returns were found to be larger for stock dividends than for stock splits. While the announcement returns cannot be explained by forecasts of imminent increases in cash dividends, the paper offers several signalling based explanations for them. These are consistent with a cross-sectional analysis of the announcement period returns.     

The effects of newly listed derivatives in a thin stock market

This study examines the informational feedback effects associated to the listing and trading of derivatives in Switzerland. The observed changes in the price and higher moments of stock returns are representative of a thin stock market. The listing of stock options and index futures generated positive abnormal returns for large stocks and for the index while small stocks essentially benefited from the launching of index options. While reducing the variance of blue chips and of the index, their variance's stochasticity increased (decreased) at index options' (futures) listings. Finally, we detect significant stock and index derivatives' price leads which do not however generate arbitrage opportunities.     

The intraday speed of adjustment of stock prices to earnings and dividend announcements

This paper examines the effects of Broad Tape news releases of earnings and dividend announcements on three aspects of intraday stock price behavior: mean returns, return variance, and serial correlation in consecutive price changes. The initial price reaction is evident in the first pair of price changes following the release (i.e., within a few minutes, at most). The returns earned by simple trading rules dissipate within five to ten minutes, although significant returns are detected in the overnight period and at the opening of trading on the next day. Disturbances in the variance and serial correlation persist for several hours and extend into the following trading day. As a class, dividend announcements induce much less activity than do earnings, although the response to dividend changes is comparable to the earnings announcement effect.     

Average correlation and stock market returns

If the Roll critique is important, changes in the variance of the stock market may be only weakly related to changes in aggregate risk and subsequent stock market excess returns. However, since individual stock returns share a common sensitivity to true market return shocks, higher aggregate risk can be revealed by higher correlation between stocks. In addition, a change in stock market variance that leaves aggregate risk unchanged can have a zero or even negative effect on the stock market risk premium. We show that the average correlation between daily stock returns predicts subsequent quarterly stock market excess returns. We also show that changes in stock market risk holding average correlation constant can be interpreted as changes in the average variance of individual stocks. Such changes have a negative relation with future stock market excess returns.     

The reaction of international stock markets to Federal Reserve policy

This paper investigates how changes in Federal Reserve policy impact international stock returns, with the three objectives of measuring the reaction of international stock markets, understanding the transmission channels of that reaction, and explaining the economic sources of that reaction. We find that unanticipated Federal Reserve policy actions exert a significant and robust influence on international stock prices. However, the influence of unanticipated monetary policy actions is not strong enough to change the correlation structure of international equity returns. We also find that international stock return co-movements play an important role in the transmission of monetary policy. Finally, the variance decomposition analysis indicates that the effects of monetary policy surprises on future excess returns or dividend returns account for the largest portion of the equity price response.     

Microstructure and reverse stock splits

In this paper we show that, similar to NYSE/AMEX stocks, NASDAQ stocks exhibit significant ex date returns for reverse stock splits. Although the 10-day cumulative return after the ex date is close to –10%, this does not violate market efficiency, because the average bid-ask spread for the reverse split stock is at least double this return. We also document that these large negative returns are mostly due to a drop in the ask price while bid prices barely change at all. Furthermore, the ex date returns are negatively related to trading volume.These results suggest that there is abnormal selling and a significant buildup of market makers' inventories near the ex date. To reduce the inventory buildup, market makers lower ask prices to induce buying by investors, resulting in the observed negative returns. Lowering bid prices, an alternative strategy for reducing inventories, is not attractive to market makers due to competitive factors and the reduction of commissions associated with a smaller number of transactions. Notably, selling investors have no incentives to sell their stocks early to avoid the observed negative ex date return, since this return is largely an ask price phenomenon and does not represent realized returns to sellers.     

The Risk‐Return Relation in International Stock Markets

We investigate the risk‐return relation in international stock markets using realized variance constructed from MSCI (Morgan Stanley Capital International) daily stock price indices. In contrast with the capital asset pricing model, realized variance by itself provides negligible information about future excess stock market returns; however, we uncover a positive and significant risk‐return tradeoff in many countries after controlling for the (U.S.) consumption‐wealth ratio. U.S. realized variance is also significantly related to future international stock market returns; more importantly, it always subsumes the information content of its local counterparts. Our results indicate that stock market variance is an important determinant of the equity premium.     

When do high stock returns trigger equity issues?

One of the most prominent stylized facts in corporate finance is that equity issues tend to follow periods of high stock returns. We document that firms exhibit such timing behavior only in response to high returns that coincide with strong institutional investor demand. When not accompanied by institutional purchases, stock price increases have little impact on the likelihood of equity issuance. The results highlight the importance of market reception for the timing of equity issues.     

Economic policy uncertainty and stock price crash risk

We examine the impact of economic policy uncertainty (EPU) on firm-specific crash risk. Based on a large sample of Chinese listed firms over the period from 2000 to 2017, we provide empirical evidence that firms are more likely to experience stock price crashes when EPU increases. Cross-sectionally analysis further reveals that the impact of EPU on stock price crash risk is stronger for firms whose returns are more sensitive to EPU. More specifically, young stocks, small stocks, high volatility stocks, and growth stocks, which have higher valuation uncertainty per se, are more sensitive to EPU and are more affected by EPU in terms of crash risk. We further show that EPU is significantly and positively associated with aggregated stock price crash risk at the market level.     

Sarbanes–Oxley Act and patterns in stock returns around executive stock option exercise disclosures

We document negative stock returns and elevated trading volumes around executives’ early option exercise disclosures post‐SOX, but not pre‐SOX. This stock price reaction is incomplete, and the negative stock price drift is smaller post‐SOX compared to pre‐SOX. We also show effects of media coverage in the stock price response to exercise disclosures in the post‐SOX period. These findings provide evidence that the requirement mandated by SOX to disclose executives’ stock option exercises within two business days, and the increased media coverage, improves investors’ ability to incorporate into stock prices in a timely fashion the information conveyed by these exercises.     

International stock return predictability

We propose a new methodology for predicting international stock returns. Our Bayesian framework performs probabilistic selection of predictors that can shift at multiple unknown structural break dates. The approach generates significantly more accurate forecasts of international stock returns than a range of popular models that are economically meaningful for a risk-averse mean–variance investor. Allowing for regime-specific variable selection reduces considerably the international diversification of an unhedged U.S. investor’s portfolio.     

Does option trading convey stock price information?

After executing option orders, options market makers turn to the stock market to hedge away the underlying stock exposure. As a result, the stock exposure imbalance in option transactions translates into an imbalance in stock transactions. This paper decomposes the total stock order imbalance into an imbalance induced by option transactions and an imbalance independent of options. The analysis shows that the option-induced imbalance significantly predicts future stock returns in the cross section controlling for the past stock and options returns, but the imbalance independent of options has only a transitory price impact. Further investigation suggests that options order flow contains important information about the underlying stock value.     

Short selling and stock returns: Evidence from the UK

The practice of shorting stocks was put forward as one of the causes of the recent financial crisis whereas Shiller (2003), for example, considers shorting an essential element of an efficient market. Shorting involves selling borrowed stocks and subsequently closing the position by purchasing and returning the stock to the lender. A profit will be realised if the stock's price decreases. Shorting enables investors who do not own a perceived overvalued stock to sell. Using a high-frequency UK dataset for the period between September 2003 and April 2010, our findings suggest shorting indicates evidence of overvalued stocks as significantly negative abnormal stock returns appear to follow an increase in shorting. These results do not hold, however, for shorting which occurs around the ex-dividend date. We further find that these results hold during the recent financial crisis.     

基本养老保险基金投资、股票收益率与股价波动性

以2017—2022年各季度基本养老保险基金投资数据为样本,考察基本养老保险基金投资对股票收益率与股价波动性的影响。结果显示：基本养老保险基金持股比例变化对股票未来收益率有一定预测效应,持股比例增加会加剧股价波动。异质性检验表明,被持股公司规模越大,持股比例变化对股票收益率的影响越不明显,对股价波动性影响的时滞性越强。对于短期持股而言,持股比例增加会加剧股价波动,而对于长期持股而言,持股比例增加有利于稳定股价。鉴于此,应继续推动基本养老保险基金全国统筹,进一步扩大其市场化投资规模、延长投资考核期限,提升基金可持续发展能力。     

Monetary environments and international stock returns

Previous research documents that US stock returns are related to the US monetary environment. The focus of this paper is to determine whether stock returns in foreign markets are associated with both local and US monetary environments. Consistent with the US market results, we find that foreign stock returns are generally higher in expansive US and local monetary environments than they are in restrictive environments. Further, these higher returns are generally not accompanied by increases in risk. Interestingly, several of the stock markets are more strongly related to the US monetary environment than to local monetary conditions. For seven of the 15 foreign countries examined, the local and US monetary environment explain 4% or more of the variation in monthly stock returns.     

Volatility increases Subsequent to NYSE and AMEX Stock Splits

The post-split increase in daily returns volatility is less for AMEX stocks than for NYSE stocks. The exchange trading location is a significant factor in explaining the volatility shift even after stock price and firm size are considered. Furthermore, when measured on a weekly basis, there is no increase in AMEX stocks' returns volatility. These results suggest that measurement errors created by bid-ask spreads and the 1/8 effect, and also one or more of the elements that make the NYSE different from the AMEX, explain why the estimated volatility of daily stock returns increases after the ex split date.     

Does Price Discreteness Affect the Increase in Return Volatility Following Stock Splits?

Stock return volatility tends to increase significantly following stock splits. One potential cause of this is the trading of stocks in discrete price intervals called ticks. This study provides a direct test of price discreteness as a determinant of this phenomenon by examining variance increases before and after the 1997 date when the exchanges reduced the tick size from 1/8 to 1/16. Results generally show that the post-split variance increase was unaffected by the reduction in tick size even after controlling for other factors. AMEX stocks proved the exception, with slightly lower variance increases following the tick size reduction.