本文探讨了2015年下半年股市异常波动以来至今持续存在股指期货巨幅贴水现象及其原因。我们首先检验了非频繁交易以及股市波动的两种解释，发现均不能很好地解释该现象。接着，我们计算了期权市场隐含的偏度风险溢价；其代表了投资者的恐慌程度和坏的尾部事件的不确定性溢价。偏度风险溢价与股指期货的VAR分析表明，股指期货价格的深度贴水可以由偏度风险溢价解释，说明投资者对崩溃风险的担心导致了投机者向套期保值者索取高额的“保险费”。股指期货的贴水幅度加深也增加了市场的偏度风险溢价，导致投资者对稀有事件不确定性索取更高的溢价。因此，完善现货市场做空机制，使得期现套利交易可行同时恢复股指期货交易，可以消除股指期货价格的深度贴水，降低投资者的对冲成本，使股指期货发挥正常的风险管理功能

This paper studies the presence of informed trading in Taiwan stock index options (TXO) and analyzes the informational role of foreign institutions in incorporating information into Taiwan stock index futures (TX). We have found that only the option-induced part (OOI) of the total TX order imbalance can predict future TX prices, and the OOI calculated from open-buy TXO, defined by Ni et al. (2008), provides incremental predictability. This finding shows that the price predictability stems from the information flow resulting from option transactions rather than from liquidity pressure. We conclude further that option transactions from foreign institutions provide the most significant predictability, out-of-the-money option transactions in particular. These empirical results show that option transactions conducted by foreign institutions have played the primary role in conveying the information inherent in the TXO market to the TX market, foreign institutions being delta-informed traders. Retail investors, the major players in both the TXO and TX markets, have done almost nothing of significance with regard to TXO information transmission into the TX market, with the exception of some near-the-money and out-of-the-money options.

股价的崩盘风险具有重要的研究价值与意义。着眼于由错误定价引发的崩盘风险，本文通过机器学习模型为每个股票-月份样本计算得到样本外崩盘风险信息，逐年样本外预测精确性的均值为89.06%，在一定程度上保证了崩盘风险信息的有效性。本文对崩盘风险信息的进一步研究发现：（1）崩盘风险的截面收益具有较高的统计与经济显著性，且具有边际的定价能力；（2）当在投资策略中加入崩盘风险的截面信息执行因子择时策略时，样本外夏普比率约为未加入的2.05倍，显示出崩盘风险的截面信息对于因子择时的突出贡献。本文的研究结果具有较强的现实意义，表现为基于崩盘风险信息，能够充分发挥资本市场中市场与非市场的力量，从而有效地降低系统性风险发生的可能性，为金融体系的健康发展保驾护航。

优胜劣汰的高质量的股票市场是金融服务经济和供给侧改革的关键。本文使用90多个财务特征指标“大数据”和多种机器学习方法提取基本面信息，对上市公司质量进行评价并构建基本面综合质量指数，研究基本面质量与股价表现的关联关系。研究分析，上市公司基本面综合质量指数对股价表现具有显著为正的预测能力。其中，由偏最小二乘法构建的质量指数对股票横截面收益的预测能力最强，年化收益接近38%，且CAPM、三因子和五因子模型对此无解释能力。我们还进一步从行为金融和宏观经济周期视角探索公司质量对股票价格的影响机制，发现市场情绪、有限套利、公司投资决策和经济周期都有助于深入理解上市公司质量溢价现象。本文研究表明，我国股票市场定价效率已经稳步提高，进入了“优胜劣汰”和价值投资阶段。

机构投资者对提升上市公司质量和市场有效性发挥了重要作用。然而，由于它们的注意力是有限的，极端收益的冲击可能会导致其注意力分散，从而抵减前述的正面效果。本文基于2008-2018年A股上市公司样本的研究表明，机构投资者注意力分散导致股价信息含量显著下降。这一关系在企业所处的治理环境较差、内部治理水平较低、信息环境较差、股票流动性较低的情况下更为显著。进一步研究表明，机构投资者注意力力分散导致上市公司的信息披露质量、机构投资者实地调研频率、交易活跃度均显著下降，且显著降低了企业价值。此外，基金层面的实证分析表明，注意力分散显著降低了基金投资组合的收益率。综上所述，机构投资者注意力分散导致其外部监督效果和知情交易积极性均显著下降，从而降低了市场的定价效率。本文的发现揭示了防范化解重大风险、培育资本市场机构投资者、提升上市公司质量等不同政策目标之间的有机关联，凸显了系统性地进行高标准市场体系建设的重要意义。

We examine a unique one day lockup constraint in stock markets in China and contribute to the understanding of impact of non-marketability on asset prices. Buyers of Chinese stocks are subject to a one day lockup and cannot sell their shares until the next day, but warrant traders are free of such restrictions. We demonstrate that the lockup creates a price discount relative to stock value implied by warrants. We show that the discount decreases throughout the trading day and that investors tend to purchase stocks when the lockup becomes less binding. The paper provides implications to value illiquid assets.

After the Chinese stock market dropped one-third in three weeks in June 2015, reportedly driven by lack of liquidity due to the fire sales by margin buyers, the government used hundreds of billions of dollars to purchase shares directly in the secondary market. We validate that margin trading is associated with the surge of stock market before the crisis. We find that firms in systemically important industries, firms with more political ties, and firms with high risk of falling into liquidity spiral are more likely to be rescued. More importantly, compared with matched un-rescued firms, rescued firms did not have higher stock return, but experienced higher volatility, lower liquidity, and lower price efficiency afterwards. Market quality even deteriorated further after the subsequent sale of the purchased shares. Last, rescued firms experience a modest decline in operational performance, while capital structure and investment remained the same. Our evidence suggest that a direct purchase rescue in the secondary stock market could generate serious unintended consequences.

知情交易者、套利交易者和噪声交易者构成期货市场的三大交易主体，共同决定期货价格。本文在两期市场中构建含知情交易者、跨市场套利者和噪声交易者的理性预期均衡模型，揭示期货聚集私人信息的微观机制、探究套利行为对现货和期货均衡价格的影响。研究发现：现货和期货市场的知情交易行为共同决定期货的价格发现水平，第二期（期货交割期）现货价格聚集私人信息的能力越强，第一期期货市场的知情交易意愿越强；套利交易对期现价格的冲击程度与知情交易者面临的交易风险正相关；套利交易有利于提高现货和期货市场的流动性，同时增加噪声冲击的跨市场传播。研究结论有助于增进投资者对期货价格发现功能和套利行为影响的理解，对提高投资者的理性交易观念、加强市场风险管理有指导作用。

信任是交易和合作的基础，对制度运行有重要影响，但文献对信任的改变知之甚少。本文使用中国健康与养老追踪调查 2011 至 2015 年的三期面板数据，以中国农村社会养老保险的政策变动作为准自然实验，研究信任的破坏与重建。实证发现， 由于老农保系统性违约， 相比未参加过老农保的家庭， 参加过老农保的家庭在新农保设立初期的参与概率降低 10.5 个百分点； 老农保缴费越多， 违约伤害越大， 参与新农保的可能性越低。随着新农保的推广，被违约的家庭逐渐重建对农村社会养老保险制度的信任：参加过老农保的家庭参与新农保的可能性逐年上升，并最终比没有参与过老农保的家庭高出 2.3 个百分点。 这一结果对个人样本稳健，并且不能被财富效应和风险因素解释。 地区法治水平和政府透明度， 农村社会养老保险制度的信息传递和有效承诺是重建信任的重要机制。 进一步研究发现， 家庭自身的教育水平和信任偏好也有助于缓解先期违约导致信任破坏造成的影响。本文对于重建信任具有重要的理论和政策涵义。

Investors have limited attention, especially when getting busy. They also possess a capability of fast thinking that requires little, if any, attention, although fast thinking leads to biased judgement and inferior outcome. From a Chinese online peer-to-peer lending market, we document a substantial amount of instant loan bids (i.e., those confirmed within only a few seconds) which help identify fast thinking. We find that lending decisions made within busy working hours with more attention constraint have significantly higher likelihood of being instant and significantly lower investment performance, suggesting that investors are prone to fast thinking when their attention becomes limited.