High-frequency traders (HFTs) accounted for roughly forty percent of trading volume on the NASDAQ Stock Market in 2009, but there is little evidence on the type of information these investors trade on. This study tests the hypothesis that HFTs anticipate and trade ahead of other investors' order flow. I find that HFTs' aggressive purchases predict future aggressive buying by non-HFTs, and their aggressive sales predict future aggressive selling by non-HFTs. The positive correlation between trading by HFTs and future trading by other investors is robust to the exclusion of trading around news releases, indicating the effect is not driven by HFTs reacting to news announcements faster than other investors. The effects are stronger in the morning and on high volume days. There are also persistent differences among HFTs in the tendency of their trades to predict future order flow. These findings have implications for the speed at which prices adjust to new information, incentives to acquire information, and the price impact of traditional asset managers' trades. / text

This article studies how short-sale constraints affect price efficiency in Brazilian stocks. The study uses a data set with all equity loan deals done in Brazil between January 2009 and July 2011. The main findings are the mapping of efficiency stock characteristics (i.e. stocks with more liquidity, larger size and greater book-to-market); an evidence of efficiency risk premium paid for investors that keep price-inefficient stocks in their portfolio; a positive relation between short selling and price efficiency and the event study of tax arbitrage, where it\'s possible to check that price inefficiency is positively related to short selling during the payment of interest on net equity. / Esta dissertação estuda os impactos da restrição à venda a descoberto na eficiência de preço dos ativos negociados em bolsa. O estudo utiliza uma base de dados com todos os negócios de aluguel de ação realizados no Brasil entre janeiro de 2009 e julho de 2011, bem como séries de preços em alta e baixa frequência para o cálculo dos índices de eficiência de preço. As principais descobertas incluem o mapeamento das características de ações eficientes (mais líquidas, empresas maiores e maior book-to-market); a evidência de um prêmio de risco a ser pago ao investidor que mantém ações menos eficientes em sua carteira; a relação positiva entre eficiência de preço e venda a descoberto e o estudo de caso da \"barriga de aluguel\", onde verifica-se, pelo aumento da restrição às operações de venda a descoberto, um aumento da ineficiência de preço ao redor de datas de pagamento de juros sobre o capital próprio.

This thesis examines the impact of FTSE 100 index revisions on the various aspects of stock market quality and the cost of equity capital. Our study spans over the period 1986-2009. Our analyses indicate that the index membership enhances all aspects of liquidity, including trading continuity, trading cost and price impact. We also show that the liquidity premium and the cost of equity capital decrease significantly after additions, but do not exhibit any significant change following deletions. The finding that investment opportunities increases after additions, but do not decline following deletions suggests that the benefits of joining an index are likely to be permanent. This evidence is consistent with the investor awareness hypothesis view of Chen et al. (2004, 2006), which suggests that investors' awareness improve when a stock becomes a member of an index, but do not diminish after it is removal from the index. Finally, we report significant changes in the comovement of stock returns with the FTSE 100 index around the revision events. These changes are driven mainly by noise-related factors and partly by fundamental-related factors.

This article studies how short-sale constraints affect price efficiency in Brazilian stocks. The study uses a data set with all equity loan deals done in Brazil between January 2009 and July 2011. The main findings are the mapping of efficiency stock characteristics (i.e. stocks with more liquidity, larger size and greater book-to-market); an evidence of efficiency risk premium paid for investors that keep price-inefficient stocks in their portfolio; a positive relation between short selling and price efficiency and the event study of tax arbitrage, where it\'s possible to check that price inefficiency is positively related to short selling during the payment of interest on net equity. / Esta dissertação estuda os impactos da restrição à venda a descoberto na eficiência de preço dos ativos negociados em bolsa. O estudo utiliza uma base de dados com todos os negócios de aluguel de ação realizados no Brasil entre janeiro de 2009 e julho de 2011, bem como séries de preços em alta e baixa frequência para o cálculo dos índices de eficiência de preço. As principais descobertas incluem o mapeamento das características de ações eficientes (mais líquidas, empresas maiores e maior book-to-market); a evidência de um prêmio de risco a ser pago ao investidor que mantém ações menos eficientes em sua carteira; a relação positiva entre eficiência de preço e venda a descoberto e o estudo de caso da \"barriga de aluguel\", onde verifica-se, pelo aumento da restrição às operações de venda a descoberto, um aumento da ineficiência de preço ao redor de datas de pagamento de juros sobre o capital próprio.

This dissertation consists of three essays in applied financial economics. The unifying theme is the use of financial regulation as quasi-experiments to understand the interrelationship between derivatives and the underlying assets. The first two essays use different quasi-experimental econometric techniques to answer the same research question: how does option listing affect the return volatility of the underlying stock? This question is difficult to answer empirically because being listed on an options exchange is not random. Volatility is one of the dimensions along which the options exchanges make their listing decisions. This selection bias confounds any causal effect that option listing may have. What is more, the options exchanges may list along unobservable dimensions. Such omitted variable bias can also confound any causal effect of option listing. My first essay overcomes these two biases by exploiting the exogenous variation in option listing that is created by the SEC-imposed option listing standards. Specifically, the SEC mandates that a stock must meet certain criteria in the underlying market before it can trade on an options exchange. For example, a stock needs to trade a total of 2.4 million shares over the previous 12 months before it can be listed. Since 2.4 million is an arbitrary number, stocks that are “just above” the 2.4 million threshold will be identical to stocks that are “just below” it, the sole difference being their probability of option listing. Accordingly, I use the 2.4 million threshold as an instrument for option listing in a fuzzy regression discontinuity design. I find that option listing causes a modest decrease in underlying volatility, a result that corroborates many previous empirical studies. My second essay attempts to estimate the effect of option listing for stocks that are “far away from” the 2.4 million threshold. I overcome the aforementioned omitted variable bias by fully exploiting the panel nature of the data. I control for the unobserved heterogeneity across stocks by implementing a two-way fixed effects model. Unlike most previous studies, I control for individual-level fixed effects at the firm level rather than at the industry level. My results show that option listing is associated with a decrease in volatility. Importantly, these results are only statistically significant in a model with firm-level fixed effects; they are insignificant with industry-level fixed effects. My third essay is a policy evaluation of the SEC’s Penny Pilot Program, a mandated decrease of the option tick size for various equity options classes. Several financial professionals claimed that this decrease would drive institutional investors out of the exchange-traded options market, channeling them into the opaque, over-the-counter (OTC) options market. I empirically test an implication of this hypothesis: if institutional investors have fled the exchange-traded options market for the OTC market, then it may take longer for information to be impounded into a stock’s price. Using the `price delay’ measure of Hou and Moskowitz (2005), I test whether stocks become less price efficient as a result of being included in the Penny Pilot Program. I perform this test using firm-level fixed effects on all classes that were included in the program. I confirm these results with synthetic control experiments for the classes included in Phase I of the Penny Pilot Program. Generally, I find no change in price efficiency of the underlying stocks, which suggests that the decrease in option tick size did not materially erode the price discovery that takes place in the exchange-traded equity options market. I also find evidence that the decrease in option tick size caused an increase in short selling for the piloted stocks. / Economics

This thesis examines the impact of FTSE 100 index revisions on the various aspects of stock market quality and the cost of equity capital. Our study spans over the period 1986¿2009. Our analyses indicate that the index membership enhances all aspects of liquidity, including trading continuity, trading cost and price impact. We also show that the liquidity premium and the cost of equity capital decrease significantly after additions, but do not exhibit any significant change following deletions. The finding that investment opportunities increases after additions, but do not decline following deletions suggests that the benefits of joining an index are likely to be permanent. This evidence is consistent with the investor awareness hypothesis view of Chen et al. (2004, 2006), which suggests that investors¿ awareness improve when a stock becomes a member of an index, but do not diminish after it is removal from the index. Finally, we report significant changes in the comovement of stock returns with the FTSE 100 index around the revision events. These changes are driven mainly by noise-related factors and partly by fundamental-related factors. / International Fellows Program, USA, (IFP) and American-Mideast-Educational and Training Services, Inc. (AMIDEAST).

Thesis advisor: James E. Anderson / This dissertation consists of two essays in international economics with a focus on the effects of exchange rate fluctuations on an economy through their impact on international capital flows and international trade. The first chapter examines the effect of exchange rate risk in foreign investors' payoff on the informativeness of security prices and home bias in portfolio holdings. I present a model with dispersed private information where foreign investors' payoff differs from domestic investors' payoff because of exchange rate changes. The equilibrium asset price aggregates private information and acts as a public signal about future payoffs. I show that higher private information acquired by foreign investors about their exchange rate adjusted payoff has two opposing effects on the information obtained by domestic investors from the equilibrium price. First, foreign investors' private information increases information about asset payoff in domestic currency, which increases information about domestic investors' payoff in the price. On the other hand, foreign investors' private information increases information about exchange rate changes, which lowers the relative information about domestic investors' payoff in the price. This second effect is higher if exchange rate volatility is high. I find support for the model's implication by using firm-level data (2000-2016) and showing that foreign institutional ownership\footnote{the fraction of common stocks outstanding that is foreign-owned} of firms from higher exchange rate volatility countries is associated with lower price informativeness. The second chapter improves on current treatment of exchange rate variation in quantitative trade models. Exchange rate changes with heterogeneous passthrough to buyers are embedded in the structural gravity model. Quantification on two digit annual bilateral trade data reveals real effects of exchange rate changes on producers that are substantial for some country-sector-time period observations. Real national income effects are small but not always negligible. Effective exchange Rates with Gravitas (ERGs) are introduced as theory-consistent indexes to guide potential policy remedies. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

許多研究指出開放外資投資國內股票市場的好處，但卻很少文獻探討外資是否有促進市場效率的功能。因此本研究旨在探討外資持股比例的高低是否會影響公司價格效率性。我們使用台灣證券交易所的資料，以2007至2016年間所有外資持股的台灣上市公司為樣本，進行分析。其中，我們使用日報酬的一階自我相關係數來衡量價格效率性，當係數趨近於零時，表示價格是有效率的且遵循隨機漫步。研究結果顯示，在台灣股票市場，無論是整體股票市場，或是分別以各產業及外資持股高低的四個組合來看，外資持股比例的增加並沒有助於公司價格效率性的提升。 / Various benefits of opening a market to foreign investors are indicated in prior studies. However, few studies point out whether foreign investors improve efficiency of stock prices. Using a large sample of TWSE-listed stocks over the period 2007 to 2016, we investigate the relation between foreign ownership and price efficiency. In our analysis, we use the first-order return autocorrelations, which should be zero if prices follow a random walk to compute price efficiency. After controlling for the change in foreign ownership, firm size, stock price and stock liquidity, finally, we find that stocks with greater foreign ownership are not priced efficiently whether in overall market or in each level of foreign ownership and also in different industries. In summary, these results suggest that the foreign investors could not improve price efficiency on the Taiwan stock market.

This dissertation consists of three essays. The first essay studies the impact of indexing on stock price efficiency. Indexing has experienced substantial growth over the last two decades because it is an effective way of holding a diversified portfolio while minimizing trading costs and taxes. In this paper, we focus on one negative externality of indexing: the effect on efficiency of stock prices. Based on a sample of large and liquid U.S. stocks, we find that greater indexing leads to less efficient stock prices, as indicated by stronger post-earnings-announcement drift, greater deviations of stock prices from the random walk and greater return predictability from lagged order imbalances. We conjecture that reduced incentives for information acquisition and arbitrage induced by indexing are probably the main cause of the degradation in price efficiency, but we find no evidence supporting a direct impact from passive trading or any effect through liquidity. The second essay investigates the effect of price inefficiency on idiosyncratic risk and stock returns. I finds that price inefficiency in individual stocks contributes to expected idiosyncratic volatility. If idiosyncratic risk is priced, greater price inefficiency could be associated with higher expected returns. Consistent with this hypothesis, this paper then finds a positive relation between price inefficiency and future stock returns. This return premium of price inefficiency is not explained by traditional risk factors, illiquidity, or transactions costs. It is also evidently different from the return bias related to Jensen's inequality. This paper thus provides new insights about the determinants of expected stock returns, and new supporting evidence that idiosyncratic risk is priced. The third essay examines whether the upward return bias generated by Jensen's inequality could lead to better performance of equally-weighted (EW) indexes than value-weighted (VW) index when stock prices are not fully efficient. We find that, for a wide range of U.S. stock indexes, EW indexes deliver better four-factor adjusted returns than VW ones do even after deducting transaction costs. Consistent with our hypothesis that the outperformance of EW indexes comes from mispricing, we find that this outperformance concentrates in stocks with greater mispricing, as measured by deviation of stock prices from random walk. Findings in this essay not only imply a potentially winning investment strategy, but also provide new insight into a long-term debate on causes of the outperformance of the EW indexes. / Ph. D.

近年來，網際網路(Internet)快速發展，已成為一個無疆無界無時差的市場，如何不被這股潮流所淘汰，我們所提出的解決方案—軟體代理人(software agent)，一位具有人工智慧(artificial intelligence)演化調適(adaptive)能力的代理人，現在已經有許多企業與資訊、管理、電腦科學等各方面專家結合，開始使用軟體代理人來代勞，試想一位永不停止、具有創新、學習適應的員工，企業家可以隨意複製或刪除，隨時配合市場規模，不必擔心任何裁員的負擔，這樣的代理人的問世，勢必對我們的經濟環境帶來莫大的衝擊。 電子商務(electronic commerce)已經行之有年，人類的消費型態似乎不易於因這個轉變而有所改變，消費者如果沒有經過視覺、觸覺、嗅覺等感官的刺激，很難有購買的動機，再加上授信制度的不健全使得電子商務的施行充滿了風險。雖然有這麼多問題，我們仍無法阻擋這股趨勢，在電子科技的進步，3D數位影像、各種感官刺激的傳送、或如同期貨市場上明確公認的規格、法律的修訂、完善的認證制度，接下來我們就是要看軟體代理人的表現。 我們將軟體代理人運用在人工雙方喊價(artificial double auction)的市場，就像真實市場已經有人開始使用自動下單或自動議價代理人的機制一樣。然而市場上是否有必然不敗的策略呢？本文就是要解開這個答案。再進一步來看，待真實市場每個成員受不了生存競爭的壓力，也採取使用代理人的演化性策略，屆時我們的人工市場就是真實市場的縮影，我們在本文也會針對這樣一個具有未來前瞻性市場的表現如何？透過經濟學的角度來揭露市場的本質是否仍然維持？ 在本文軟體代理人即為議價代理人(bargaining agent)，她可以在穩定的(stable)市場環境(其他參與者使用固定策略)中辨別出一些有利的市場特徵，藉由這些特徵發展出有利的策略，而其結果甚至不是很容易想到的策略；接著若每個人都使用議價代理人在市場上交易，這裡我們使用一種納許式過程(Nash-like process)來詮釋，之後再分別依市場的分配效率、價格效率、及所得分配來討論市場績效。