venerdì 24 settembre 2010

Come sopravvivere a un mercato bipolare?

Ho trovato divertente la definizione di "mercato bipolare" in questo articolo del WSJ che giustamente inizia osservando come

The stock and bond markets are swinging daily between optimism and despair. Given all the whipsawing, you might be tempted to write the whole thing off and stay in cash.
But three easily followed indicators can help you make sense of today's chaotic, macro-driven trading environment—and maybe even get out in front of the next big move.
Just how volatile have the markets been? The Dow Jones Industrial Average fell 4.3% last month, the worst August in nine years, as fears of deflation and a double-dip recession spread. In September, better economic data and increased merger activity have propelled the Dow to a 5.8% jump, the biggest since at least 1990 for the month if the market holds on to its gain.
Or consider this: If the Standard & Poor's 500-stock index keeps its 7.5% September gain, it will be the fifth consecutive month with a move of at least 4.5% in either direction, which has happened only three times since the 1930s, according to hedge fund Lakefront Partners: in 1974, 1998 and 2009. 

Stando attenti a non cadere nella tentazione di applicare la "legge dei piccoli numeri" di Kahneman e Tversky, e alla nostra innata tendenza a generalizzare a partire dalla conoscenza di pochi casi fortunati,  ci si può comunque chiedere in tempi così volatili se c'è modo di orientarsi e di utilizzare qualche indicatore macro per decidere se è il tempo di scappare via dalle azioni oppure no. Secondo il WSJ è utile tenere d'occhio l'Institute for Supply Management's Manufacturing Index:

The ISM and the S&P 500 tend to move together. Their so-called correlation is currently 0.911, the highest since touching 0.95 in November 2009. Over the long term, the correlation between the ISM and the year-over-year change in the S&P has jumped from 0.3 in the 1970s to 0.8 now. (A reading of 1 means they always travel in lockstep; a reading of -1 means they always move in opposite directions.)

In the past few years the ISM has helped confirm turns in the market. (...)
"This is a directional indicator for six- to 12-month strategic positioning," says Talley Leger, vice president of U.S. portfolio strategy for Barclays Capital.
The next ISM Manufacturing number is scheduled to be released on Oct. 1.

Oggi i mercati fanno festa, trascinati proprio dai buoni risultati dell'industria manifatturiera.  Per il futuro
staremo a vedere, senza dimenticare che ottobre è uno dei mesi particolarmente pericolosi per gli investimenti azionari, come d'altronde gli altri 11 (Mark Twain docet...)

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