finance168財經學院(百萬部落格)

The European debt crisis can easily feel like an unwieldy, unmanageable mess of complex jargon and financial terms. Here’s Wonkblog’s explanation of what’s happening across the Atlantic Ocean with the help of eight key graphs:

The place to start with the European debt crisis is, well, with European debt. Put simply, the crisis in the euro zone is that the market doesn’t trust that Greece, Italy, Spain, Ireland and Portugal can pay back their debts, and so they don’t want to lend them more money except at exorbitant rates.

But to understand how Europe got into this mess, how countries like Greece managed to borrow so much money that they couldn’t pay it all back, you need to see this graph from the Organization for Economic Development and Cooperation (OECD). On the right side, you’re seeing the story everyone already knows: The market is charging Southern European countries a lot to borrow. But look at the left side. As recently as 2008, the market was lending to Greece and Germany at pretty much the exact same price. The assumption was that the euro could never break up, and thus everyone in it was as safe a bet as the safest, biggest economy on the euro: Germany.

筆者是位紅酒迷，最近搶到了一箱超級年份2009年的香貝丹(chambertin)，而香貝丹素有勃根地貴族世家之稱，為表達個人的喜悅，特作此文饗宴讀者。

小撈與兩光在荷西諾餐酒會

從眾行為

從眾行為是指投資人在某段期間內，針對有價證券進行相同方向的交易，例如同時買入或同時賣出。散戶的從眾行為是基於非理性的追求流行趨勢結果，而法人的從眾行為依據財務學家Sias的分類，是由於information cascades, investigative herding, reputational herding, fads, characteristic herding等五項因素造成的。

information cascades是指法人會忽略自己本身的資訊，卻觀察他人的交易進行從眾交易，從眾者主觀的認為他人的決策包含有用的資訊，因而拋棄自己原有的資訊，轉而跟隨他人的決策，當此過程一再被重複時，這種行為就會如同瀑布不斷的向下匯集，變成集體性的從眾行為。

    人類最容易出現的另一個行為就是過度自信，它其實是指你有better than the average或是自我感覺良好的心態。根據一項跨國際汽車駕駛技術的調查，超過85%的司機認為駕車技術優於平均，這就是一種過度自信，因為明顯只有50%的司機技術會優於平均，可見至少有35%的司機有過度自信傾向。

在行為財務學裡，普遍認為過度交易是由於過度自信造成的，而過度交易會導致交易傭金的增加，因而導致投資績效的下降，因此，你要增加投資績效，就要避免買賣過程中的過度交易。那麼過度自信是如何形成的？過度自信對市場又會有什麼影響呢？