隨著全球化繼續增強資本市場的聯系，蝴蝶效應的概念在金融世界變得重要起來。國際市場中一個小區域的波動可以迅速增長並蔓延到其他市場，一個小角落的市場波動可以引起全球波動。科技的進步和廣泛的互聯網使用增加了國際市場的互相影響。這導致了更多極端的市場波動。
蝴蝶效應在流行文化中已經衆所週知，這一概念也被應用到了金融領域。它和混沌理論可以為資本市場的不可預測性提供部分解釋。
蝴蝶效應的起源和意義
蝴蝶效應一詞最初出現在1972年的一次科學會議上。是科學家Edward Lorenz在他的天氣預測模型中提出了這一詞匯。這一詞的含義是日本一只蝴蝶煽動翅膀引起的小型大氣變化可能最終導致德克薩斯州的一場龍卷風。
Lorenz在麻省理工學院研究了最小初值的變化是怎樣引起大規模天氣模型的不同的。1961年，他用初始條件為0.506的天氣模型得出了與精確數值0.506127天氣模型完全不同的和不可預測的天氣模式。1963年，他撰寫了關於這一概念的報告，名為《決定性的非週期流》。蝴蝶效應的概念表明動態系統是非常難預測的，例如天氣和金融市場。蝴蝶效應的研究導致了混亂理論的發展。
混亂理論在市場中的應用
資本市場中包含平穩和劇烈波動的交替。然而，這些交替不總是無序的，他們之間的轉換通常是突然和不可預測的。一些人相信混亂理論的概念能夠用於理解金融市場是怎麼運行的。
市場傾向於增加泡沫並最終導致極端的結果。金融泡沫經常因為積極的反饋而產生。當一些投資者在一個金融市場的上漲階段中賺錢，其他觀察者認為這些投資者一定是做出了明智的決定，導致這些觀察者把自己的資金也投入到市場中。結果將是買家增多使股價繼續上漲。這一積極反饋導致價格超過合理水平。在循環結束時，最終剩下的投資者將會遭受損失。
相同的概念可以解釋不穩定的熊市。市場可能因為外部因素突然轉移，導致投資者只關註負面新聞。最初的出售可以導致投資者在清算倉位時更多的抛售。負面反饋生效非常快，最終導致整體市場股票價值被低估。
分型學和市場
著名科學家Benoit Mandelbrot把分型學應用到金融市場中。他發現自然界中的混亂例子，例如海岸線或者雲朵的形狀，通常擁有高度的秩序。這些分型形狀也能用於解釋混亂系統，包括金融市場。Mandelbrot指出資產價格可以沒有明顯原因的突然跳動。
大多數市場中極端事件發生的概率不到5%。Mandelbrot認為這些異常值非常重要並在金融市場走勢中扮演了重要的角色。傳統的投資組合理論傾向於低估這些高波動性事件發生的頻率。雖然分型學不能預測價格波動，但他認為可以更加現實的預測市場風險。
市場中蝴蝶效應的例子
盡管科技增加了蝴蝶效應在全球市場中的影響，但是還是有一個歷史悠久的金融泡沫，那就是17世紀荷蘭的郁金香市場泡沫。郁金香是一個精英身份的象徵。它們在荷蘭城市和村鎮交易所交易。人們出售財產進行郁金香投機。然而，價格開始下降，恐慌抛售隨之而來。
近期市場泡沫的例子更多。在1987年的黑色星期一中，道瓊斯工業指數在一個交易日中下跌了約22%，這是有史以來最大的單日跌幅。雖然在一週前道瓊斯工業指數出現過幾天大幅下跌並且海灣地區有國際事件發生，但是下跌沒有明顯的原因。回想起來，也許程式交易是恐慌性抛售的一部分原因。
2015年，中國股票市場出現劇烈波動，在一個交易日中下跌8%。與黑色星期一類似，也沒有出現下跌的明顯原因。這一波動很快蔓延到了其他市場，標準普爾和日經指數下跌了4%左右。還是和黑色星期一一樣，在前幾個月中國市場也出現了疲軟。
當時中國政府已經開始進行人民幣貶值。然而，主要原因可能是中國散戶開始大量使用保證金。當價格開始下跌，投資者受到追加保證金要求。散戶被迫平倉以滿足追加保證金要求，導致了抛售的負面反饋循環。在之前的幾年，中國政府鼓勵人們將資金投放入市場。隨著技術的進步和提高，市場的連通性會進一步提高，蝴蝶效應將繼續是全球市場的一個影響因素。
Globalization and the Butterfly Effect
By John Edwards
The butterfly effect concept has become important in the finance world as globalization continues to increase and capital markets connect. Volatility in one small area of the international markets can grow rapidly and bleed into other markets, and a hiccup in one corner of the international markets can have global consequences. Improvements in technology and wider access to the Internet has increased the degree to which international markets influence each other. This has led to more episodes of extreme market volatility.
The butterfly effect has become well-known in popular culture, and the concept has clear applications to finance. It and chaos theory may provide a partial explanation for the unpredictability of capital markets.
Origin and Meaning of Butterfly Effect
The phrase "the butterfly effect" was first coined during a scientific meeting in 1972. Scientist Edward Lorenz gave a talk on his work regarding weather prediction models. The phrase suggests that the flap of a butterfly's wings in Japan could create a small change in the atmosphere that might eventually lead to a tornado in Texas.
Lorenz studied how small differences in initial values led to large differences in weather models at the Massachusetts Institute of Technology. In 1961, he had entered an initial condition in a weather model as 0.506, rather than the precise number of 0.506127, which resulted in a completely different and unexpected weather pattern. In 1963, he wrote a paper on this concept, titled "Deterministic Nonperiodic Flow." The butterfly effect concept shows how difficult it is to predict dynamic systems, such as weather and financial markets. Study of the butterfly effect has led to advances in chaos theory.
Application of Chaos Theory to Markets
Capital markets go through alternating periods of calm and storminess. However, they are not always chaotic, and the shift between calm and chaos is often sudden and unpredictable. Some believe that these concepts of chaos theory can be used to understand how financial markets operate.
Markets tend to grow bubbles that eventually pop with drastic consequences. Financial bubbles often grow because of positive feedback. When investors make money during a rise in the financial markets, other observers think the investors must have made a smart decision, which leads the observers to invest their own money in the markets. The result is more buying and stock prices going higher. The positive feedback loop leads to prices beyond any logical or justifiable level. The loop eventually ends, and the last investors in are left hanging with the worst positions.
The same concept can explain volatile bear markets. The markets can suddenly shift due to outside factors, which causes investors to pay attention only to negative news. Initial selling leads to more selling as market participants liquidate their positions. The negative feedback loop tends to accelerate quickly, often resulting in a market full of undervalued stocks.
Fractals and the Markets
Prominent scientist Benoit Mandelbrot applied his work in fractals in nature to financial markets. He found that examples of chaos in nature, such as the shape of shorelines or clouds, often have a high degree of order. These fractal shapes can also explain chaotic systems, including financial markets. Mandelbrot noted that asset prices can jump suddenly with no apparent cause.
Many in the markets tend to dismiss the extreme events that occur less than 5% of the time. Mandelbrot argued that these outliers are important and play a significant role in financial market movements. Traditional portfolio theory tends to underestimate how often these high-volatility events occur. While his fractals cannot predict price movements, he argued that they could create a more realistic picture of market risks.
Examples of the Butterfly Effect in Markets
Although technology has increased the impact of the butterfly effect in global markets, there is a long history of financial bubbles going back to the tulip market bubble in Holland during the 17th century. Tulips were a status symbol among the elite. They were traded on exchanges in Dutch towns and cities. People sold their belongings to begin speculating on tulips. However, prices began to drop and panic selling ensued.
There are more recent examples of bubbles. On October 1987, known as Black Monday, the Dow Jones Industrial Average (DJIA) lost around 22% in one trading day, the largest percentage drop ever for that market. There was no apparent cause for the drop, though the DJIA had some large down days the week before, and there were international issues in the Persian Gulf. In retrospect, issues with panic selling and perhaps program trading might be partly to blame.
In 2015, the Chinese stock market encountered significant volatility, dropping over 8% in one day. Similar to Black Monday, there was no single event or cause for the drop. This volatility quickly spread to other markets, with the S&P500 and the Nikkei losing around 4%. Also like Black Monday, there had been weakness in the Chinese markets in prior months.
Chinese officials had begun devaluing the renminbi. However, the main cause was likely the high degree of margin used by Chinese retail investors. When prices began to drop, investors received margin calls from their brokers. Retail investors were forced to liquidate their positions quickly to meet the margin calls, leading to a negative feedback loop of selling. In years prior, the Chinese government encouraged people to put their money in the market. Markets will only become more interconnected as technology continues to improve, and the butterfly effect will continue to be a factor in global markets.
本文翻譯由兄弟財經提供
文章來源：http://www.investopedia.com/articles/investing/021716/globalization-and-butterfly-effect.asp