In modern finance, a flash crash is a very rapid, deep, and volatile fall in security prices occurring within a very short time period followed by a quick recovery.[1] Flash crashes are frequently blamed by media on trades executed by black-box trading, combined with high-frequency trading, whose speed and interconnectedness can result in the loss and recovery of billions of dollars in a matter of minutes and seconds, but in reality occur because almost all participants have pulled their liquidity and temporarily paused their trading in the face of a sudden increase in risk.[2]
Occurrences
Examples of flash crashes that have occurred:
May 6, 2010, flash crash
April 23, 2013, flash crash
Frankenshock,[3] or Flash Crash Swiss Franc on January 15, 2015[4]
Flash Crash of the British Pound on October 6, 2016[5]
Flash Crash of Japanese Yen on January 2, 2019[6][7]
Flash Crash of European Stock Markets on May 2, 2022.[8][9]
2010 flash crash
Main article: 2010 flash crash
This type of event occurred on May 6, 2010 in the United States. A $4.1 billion trade on the New York Stock Exchange (NYSE) resulted in a loss to the Dow Jones Industrial Average of over 1,000 points and then a rise to approximately previous value, all over about fifteen minutes. The mechanism causing the event has been heavily researched and is in dispute. On April 21, 2015, the U.S. Department of Justice laid "22 criminal counts, including fraud and market manipulation" against Navinder Singh Sarao, a trader. Among the charges included was the use of spoofing algorithms.[10]
2017 Ethereum Flash Crash
On June 22, 2017, the price of Ethereum, the second-largest digital cryptocurrency, dropped from more than $300 to as low as $0.10 in minutes at GDAX exchange. Suspected for market manipulation or an account takeover at first, later investigation by GDAX claimed no indication of wrongdoing. The crash was triggered by a multimillion-dollar selling order which brought the price down, from $317.81 to $224.48, and caused the following flood of 800 stop-loss and margin funding liquidation orders, crashing the market.[11]
British pound flash crash
On October 7, 2016, there was a flash crash in the value of sterling, which dropped more than 6% in two minutes against the US dollar. It was the pound's lowest level against the dollar since May 1985. The pound recovered much of its value in the next few minutes, but ended down on the day's trading, most likely due to market concerns about the impact of a "hard Brexit"—a more complete break with the European Union following Britain's 'Leave' referendum vote in June. It was initially speculated that the flash crash may have been due to a fat-finger trader error or an algorithm reacting to negative news articles about the British Government's European policy.[12]
USDJPY and AUDUSD flash crash
On January 2, 2019, a flash crash was seen in the value USDJPY and AUDUSD, which dropped more than 4% in a few minutes. It was the USD lowest level against the Yen and AUD against USD since March 2009. The USDJPY and AUDUSD recovered much of its value in the next few minutes. It was speculated that the flash crash may have been due to Apple reporting reduced sales forecast in China but this seems unlikely as the report came out an hour before the actual crash.[13] The lows reported on USDJPY also varied with Reuters reporting a low of 104.90 on USDJPY while FXMarketAPI reported a low of 104.45.[14]
Flash Crash of European Stock Markets on May 2, 2022
On May 2, 2022, from 9:56 to 10:01 CET the Swedish OMXS30 index dropped 6.8%, the Norwegian OBX 4.1%,[15] the Danish OMXC25 -6.7% and the Finnish OMXH25 -7.5%.[16] Other European indices dropped too, although not as severely as the Nordic exchanges. The German DAX dropped 1.6%[17] and the European STOXX 600 2.2%.[18] At their lowest point around €300bn or $315bn had been erased from the markets.[19] The indices quickly rebounded to levels at or slightly below what it was before the crash. A spokesperson for Nasdaq said the crash was not because of internal server errors or hacker attacks. Nasdaq stated that trades done during the crash would not be cancelled on the exchanges that it operates.[20] There were rumors that Citigroup had accidentally sold a large basket of European stocks over the market.[21] Later in the afternoon Nasdaq confirmed that the flash crash was due to a very large accidental sell order by a market participant, a so-called fat-finger error. Nasdaq would not comment which market participant it was.[22] Later in the day Citigroup admitted that the crash was caused by "an error when inputting a transaction" by one of its traders at their London trading desk.[23]
Other crashes
In October 2013, a flash crash occurred on the Singapore Exchange which wiped out $6.9 billion in capitalization and saw some stocks lose up to 87 percent of their value. The crash resulted in new regulations being announced in August 2014. Minimum trading prices of 0.20 cents per share would be introduced, short positions would be required to be reported, and a 5 percent collateral levy implemented. The exchange said the measures were to curb excessive speculation and potential share price manipulation.[24]
Two short-lived (less than a second) movements (more than 1%) in several (40 and 88) stock prices followed by recovery were reported for November 25, 2014.[25]
SQL(聆聽i/ˈɛs kjuː ˈɛl/[ 4 ]或聆聽i/ˈsiːkwəl/[ 5 ],Structured Query Language,結構化查詢語言[ 6 ][ 7 ][ 8 ][ 9 ])是一種特定目的程式語言,用於管理關聯式資料庫管理系統(RDBMS),或在關係流資料管理系統(RDSMS)中進行流處理。 SQL基於關係代數和元組關係演算,包括一個資料定義語言和資料操縱語言。SQL的範圍包括資料插入、查詢、更新和刪除,資料庫模式建立和修改,以及資料存取控制。儘管SQL經常被描述為,而且很大程度上是一種聲明式編程(4GL),但是其也含有程序式編程的元素。 SQL是對埃德加·科德的關係模型的第一個商業化語言實現,這一模型在其1970年的一篇具有影響力的論文《一個對於大型共享型資料庫的關係模型》[ 10 ]中被描述。儘管SQL並非完全按照科德的關係模型設計,但其依然成為最為廣泛運用的資料庫語言。 [ 11 ][ 12 ] SQL在1986年成為美國國家標準學會(ANSI)的一項標準,在1987年成為國際標準化組織(ISO)標準[ 13 ]。此後,這一標準經過了一系列的增訂,加入了大量新特性。雖然有這一標準的存在,但大部分的SQL代碼在不同的資料庫系統中並不具有完全的跨平台性。 參考文獻 Paul, Ryan. A guided tour of the Microsoft Command Shell. Ars Technica. [10 April 2011]. (原始內容存檔於2018-12-25). Media Type registration for application/sql. Internet Assigned Numbers Authority. 10 April 2013 [10 April 2013]. (原始內容存檔於2018-01-24). The application/sql Media Type, RFC 6922. Internet Engineering Task Force: 3. April 2013 [10 April 2013]. (原始內容存檔於2016-10-18). Beaulieu, Alan. Mary E Treseler , 編. Learnin...
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