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arXiv 1112.3095q-fin.GNphysics.soc-phq-fin.STq-fin.TR
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金融危机中操纵市场的证据

Evidence of market manipulation in the financial crisis

Vedant Misra, Marco Lagi, Yaneer Bar-Yam

摘要:

我们提供了在2007年11月金融危机开始时操纵市场的直接证据。2007年7月,美国证券交易委员会(SEC)废除了一项规定,该规定将阻止这种操纵行为,即“空头突袭”。这一规定是为了防止操纵和促进稳定,从1938年开始生效,是政府应对1929年市场崩溃及其后果的关键部分。2007年11月1日,花旗集团经历了不寻常的交易量增加和价格下降。我们对金融行业数据的分析表明,这种下跌与借入股票的异常增加相吻合,借入股票的出售将占总交易量的很大一部分。借入股票的抛售不能用新闻事件来解释,因为股东的抛售并没有相应增加。六天后的一天,也有类似数量的股票被返还。借款和归还股票的规模和巧合证明了花旗集团协同努力压低股价并实现盈利,即,熊袭击对金融市场的解释和分析应考虑到个体行为者或协调群体的故意行为可能影响市场行为的可能性。市场不够透明,甚至无法揭露重大的市场操纵事件。我们的研究结果表明,需要制定法规,防止导致市场偏离均衡并导致崩溃的故意行为。强制措施无法扭转对经济体系的严重破坏。现行的“替代”升价规则只适用于单日跌幅超过10%的股票,并不足够。可以通过改善市场数据的可用性和原有的加价规则或其他交易限制来实现预防。

英文摘要:

We provide direct evidence of market manipulation at the beginning of the financial crisis in November 2007. The type of manipulation, a "bear raid," would have been prevented by a regulation that was repealed by the Securities and Exchange Commission in July 2007. The regulation, the uptick rule, was designed to prevent manipulation and promote stability and was in force from 1938 as a key part of the government response to the 1929 market crash and its aftermath. On November 1, 2007, Citigroup experienced an unusual increase in trading volume and decrease in price. Our analysis of financial industry data shows that this decline coincided with an anomalous increase in borrowed shares, the selling of which would be a large fraction of the total trading volume. The selling of borrowed shares cannot be explained by news events as there is no corresponding increase in selling by share owners. A similar number of shares were returned on a single day six days later. The magnitude and coincidence of borrowing and returning of shares is evidence of a concerted effort to drive down Citigroup's stock price and achieve a profit, i.e., a bear raid. Interpretations and analyses of financial markets should consider the possibility that the intentional actions of individual actors or coordinated groups can impact market behavior. Markets are not sufficiently transparent to reveal even major market manipulation events. Our results point to the need for regulations that prevent intentional actions that cause markets to deviate from equilibrium and contribute to crashes. Enforcement actions cannot reverse severe damage to the economic system. The current "alternative" uptick rule which is only in effect for stocks dropping by over 10% in a single day is insufficient. Prevention may be achieved through improved availability of market data and the original uptick rule or other transaction limitations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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