Traders work on the floor of the New York Stock Exchange (NYSE) on March 09, 2020 in New York City
北京时间3月9日晚间，美国三大股指开盘大跌，道指盘初迅速跌超1800点，跌幅扩大至7%。标普500指数跌7%，触发第一层熔断机制，暂停交易15分钟，重挫使得标普500指数自2月19日创下的高位下跌近20%，
On March 9, 2020, three major U.S. stock indexes fell sharply soon after the opening bell. The Dow Jones Industrial Average sank by more than 1,800 points while S&P 500 plunged by seven percent, triggering a “circuit breaker mechanism”. As a result, the stock trading was halted for 15 minutes for the first time since 1997.所谓熔断机制，指的是股票市场的交易时间中，当价格波动的幅度达到某一个限定的目标（熔断点）时，对股市暂停交易一段时间的机制。美国推出熔断机制的动因还需追溯到1987年的“黑色星期一”。1987年10月19日，道指暴跌508.32点，跌幅22.6%。3个月之后，1988年2月熔断机制出台，于当年10月首次开始实施。在这里，市场下跌，是指标普500指数在常规交易时段(美东时间9：30-16：00)，指数点位相对于前一日收盘点位的下跌。一般都是有证券承销资格的投资银行等证券中介公司，所以我们通常称他们为卖方。（当然一级市场中的投资银行也有自己的买方职能，比如GSAM，JPMAM等等，不过不属于传统的投行职能。）二级市场是指在证券发行后各种证券在不同的投资者之间买卖流通所形成的市场，又称流通市场或次级市场。比如上海证券交易所和深圳证券交易所。三级市场就是退市的股票和因历史遗留问题而未能上市交易的股票交易的市场。What is circuit breaker mechanism? The circuit breaker mechanism refers to measures adopted by stock exchanges to temporarily halt trading to avert panic selling by investors after the stock index has fallen a certain percentage. The primary market is where securities are created. It's in this market that firms sell (float) new stocks and bonds to the public for the first time. An initial public offering, or IPO, is an example of a primary market.The secondary market is where investors buy and sell securities they already own. It is what most people typically think of as the "stock market," though stocks are also sold on the primary market when they are first issued.A third market consists of trading conducted by non-exchange member broker-dealers and institutional investors of exchange-listed stocks.在欧佩克减产协议无疾而终后，沙特阿拉伯大幅降低售往欧洲、远东和美国等市场的原油价格，折扣幅度为20年来增幅最大，与此同时，沙特加大了原油增产量。此举被视为对俄罗斯的报复行为，其意图为了将其他高成本生产商挤出原油供应市场。受此影响，全球原油价格暴跌。3月10日早间，布伦特原油期货大幅跳水，单日跌幅，均创下十年来新高。3月9日，经历15分钟暂停交易“冷静期”后的市场，重新开盘后，市场热度依然不高。表征市场恐惧心理的CBOE波动性指数VIX一天之内飙涨30%。此次油价大跌引发的恐慌情绪指数（VIX）迅速在整个市场蔓延，触发熔断，成为“慌乱”的外显。Saudi Arabia has decreased the price of crude it sells to markets such as Europe, the Far East and the U.S., at the biggest discount in two decades. After the failure of an OPEC+ deal to cut output, it even ramped up its oil production. Analysts see such acts as retaliation against Russia in an attempt to squeeze other high-cost producers out of the market. As a result, the global price of crude oil plunged. On March 10, Brend Crude futures fell sharply, hitting its lowest point in a decade. After a 15-minute "cooling-off period" on March 9, the market remained subdued. The CBOE volatility index (VIX), rose by 30 percent in one day. The VIX triggered by the sharp drop in oil prices quickly spread through the market, triggering a circuit breaker and investors' "panic" towards the market. 全球疫情的不可知性，让市场失去评估经济基本面走势的指标，分析员们也担心难以预测，且不同寻常的事件会引起市场连锁的负面反应，俗称“黑天鹅事件”。此外，美联储的独立性和能力的存疑，也让人们失去了对后续政策定位的标准。The unpredictability of the COVID-19 outbreak has left markets without an indicator to access the fundamental indicator of the economy. In addition, analysts doubt the Federal Reserve's independence on making economic policy, as people have also lost their criteria for the follow-up policyCGTN驻纽交所记者John Terrett表示，两个国际因素正在对股市进行双重打压，一个是昨晚沙特-俄罗斯引发的原油价格暴跌带来的冲击，另一方面是新冠肺炎疫情的影响。低油价对于司机是好消息，对于进口原油较多的印度也是好消息，但对于新兴市场与对本国货币与美元挂钩的国家来说不容乐观。As CGTN American’s John Terrett said, there are two international issues pressing down on the global stocks. One is the overnight Saudi-Russian oil shock, which started last Friday but they couldn’t get on the same page over the weekend. The other thing is the spread of COVID-19. Lower oil prices are good for ordinary consumers, good for countries like India that import oil but not so good for emerging markets and countries that peg their currencies to the U.S. dollar. 他表示，沙特压低原油价格的事件对消费者来说是“好事”，假新闻的炒作加上沙特与俄罗斯为了石油减产的博弈，都是导致股市下跌的原因。特朗普9日在新闻发布会上表示，将与国会讨论降低薪资税的可行方案。