上周末，沃倫?巴菲特公布了致伯克希爾-哈撒韋公司股東的年度信件。和過去一樣，這封信妙語連珠，令人難忘，巴菲特也在其中點評了美國的經濟現狀。但大多數人似乎都沒有發現，這位奧馬哈先知還在今年的信中提出了一些投資建議，而且堪稱他曾寫下的最佳建議。

這可能是因為這些建議沒有出現在探討投資或股市的章節，而是放在了和保險相關的部分。在詳細介紹伯克希爾旗下通用再保險公司的業績時，巴菲特用一段有意思的文字提出了保險公司必須遵循的四條原則。他寫道：

說到底，情況良好的保險公司需要遵循四條原則：第一，它必須了解所有可能讓保單出現損失的風險；第二，它必須保守地評估所有風險真正帶來損失的幾率以及可能由此產生的成本；第三，扣除潛在損失成本和經營費用后，它設定的保費平均而言必須能產生利潤；第四，如果保費無法達到適當水平，它必須愿意放棄這筆生意。

這段話讓我想到了投資管理（老實說，它差不多占據了我的全部思緒）。保險和投資的相似度幾乎達到100%，這一發現讓我深受感觸。畢竟，除了作為今后開支和需求的保障，投資還能是什么呢？

現在就讓我們逐一探討這四大原則：

原則1：了解所有可能讓保單出現損失的風險。

首先，讓我們從長期投資者的角度來定義一下“損失”。它是指永久失去一定數量資金的可能性。債券或股票都可能帶來損失。在某些情況下，共同基金也是如此。就連指數基金也可能造成損失，條件是它追蹤的指數再也回不到之前的高點。

相反，多元化投資幾乎永遠也不會帶來永久性損失，除非持有人的某些行為導致這種結果。如果在市場底部拋售各類資產，或者在市場中某個不明朗的領域投入過多，投資者的資金絕對會一去不復返。

據我所知，防止發生這種情況的唯一途徑就是多元化并進行系統性再平衡。多元化投資不能避免階段性損失，但這樣的損失更有可能是縮水，而不是永久性虧損。對一位把全部資金投入本國股市的日本投資者來說，相對于25年前日經指數的高點，他的投資仍處于縮水狀態。如果他進行全球性配置，多元化投資可能早就幫他挽回了損失，眼下的投資表現可能也會好得多。

原則2：保守地評估所有風險真正帶來損失的幾率以及可能由此產生的成本。

在不利情況或市場動向的影響下，你可能損失多少？出現大幅縮水的幾率有多高？情況會變得有多差？在既定回報率下，你愿意承擔多少市場波動風險？通過了解以往各類資產下跌的可能性，投資者就應該知道如何構建自己的投資。人們常說，只要能看到自己的風險，上升潛力自然就會浮現。

原則3：扣除潛在損失成本和經營費用后，設定的保費平均而言必須能產生利潤。

這一點怎么強調都不過分。有些風險能帶來收益，但有些收益并不值得投資者去冒險。

集中投資風險絕對屬于后一種。將大筆資金投入少量投資對象確實是生財之道，但這只能是后見之明。對大部分人來說這種做法都行不通，但大家很少聽說這樣的事。我們聽到的許多事例都是過去時，而且內容都是所謂的聰明人把資金集中在某個方面，然后大賺了一筆。

不同的資產類別有不同的風險和回報幾率。股票的長期回報最高，但和投資級固定收益資產的持有者相比，持股者經歷的考驗必定更多。舉例來說，就整個投資行為而言，關鍵就是在潛在風險承受度和未來收益需求度之間求得平衡。按照這樣的思路，你的“經營費用”就是退休后的負債，如果你在為子女教育存錢，這些費用就會出現的更快。在各種各樣的行情下，你都能承擔這些費用嗎？如果你自己回答不了這個問題，那就跟金融規劃師談談。

原則4：如果保費無法達到適當水平，必須愿意放棄這筆生意。

某些情況下，投資風險會遠遠超過承擔這些風險而應得到的“保費”，也就是回報。最近的一個例子是，許多投資者都放棄了通常會購買的債券，轉而投資于業主有限合伙制公司。為獲得7%的股息收益率，投資者對這些公司趨之若鶩。但隨著油價下跌，這些公司的股價在過去一年中平均下降了40%，由此產生的損失相當于這些投資者六年的股息收入。

那些為提高當前收益而承擔垃圾債券信用風險的投資者最近也得到了類似的教訓。在某個時刻，用高收益必需消費品股和債券建倉，或者承擔著長期美國國債利率風險的投資者也會面臨投資縮水局面。參與掉期交易或者購買了金融機構發行的債務抵押證券，從而承擔了對手方風險的投資者也是如此。

結論：華爾街沒有免費午餐，幾乎每種資產都有獨特的風險。不過，為了今后的回報而承擔眼下的風險并沒有錯，只是要確保自己在這個過程中獲得足夠的潛在回報。沃倫?巴菲特顯然做到了這一點。而且，他得到的回報一直都沒有這么低。(財富中文網)

譯者：Charlie

校對：詹妮

This weekend, Warren Buffett released his annualletter to Berkshire Hathaway shareholders. As always, it was full of memorable quips and the Oracle’s take on where the US economy currently stands. But what most people seem to have missed is that this year’s Berkshire BRK.A 0.00% letter also contained some of the best investment advice the Oracle of Omaha has ever written down. That’s perhaps because it was in a portion not devoted to investing or the stock market, but insurance. In the section of the letter detailing the results of Berkshire’s General Re subsidiary, there was an interesting tidbit on the four disciplines that must be adhered to in the insurance business. Buffett wrote:

At bottom, a sound insurance operation needs to adhere to four disciplines. It must (1) understand all exposures that might cause a policy to incur losses; (2) conservatively assess the likelihood of any exposure actually causing a loss and the probable cost if it does; (3) set a premium that, on average, will deliver a profit after both prospective loss costs and operating expenses are covered; and (4) be willing to walk away if the appropriate premium can’t be obtained.

This got me thinking about portfolio management (which is pretty much all I ever think about, let’s be honest) and it struck me that the parallels between insurance and investing were pretty perfect. What else, after all, does a portfolio represent but insurance for the expenses and needs of the future?

Let’s take these four disciplines one by one:

Understand all exposures that might cause a policy to incur losses.

First, let’s define “losses” from the standpoint of a long-term investor: It’s the possibility of having a quantity of money permanently go away. This can happen in a bond or an individual stock. In some cases, it can happen in a mutual fund. It can even happen in an index fund if it tracks an index that makes a high it never returns to.

But a diversified portfolio will almost never incur a permanent loss other than due to the behavior of the investor holding it. By selling asset classes at a market bottom or wagering too heavily in an obscure area of the market, investors can absolutely cause themselves permanent losses.

The only way to guard against this outcome that I am aware of is diversification and systematic rebalancing. A diversified portfolio cannot avoid periods of loss, but these periodic declines are more likely to be drawdowns as opposed to permanent losses. A Japanese investor with a 100% domestic stock portfolio invested in the Nikkei could still be in drawdown from the market’s peak 25 years ago. That same investor with a globally allocated, diversified portfolio would have recouped his losses long ago and would be doing much better today.

Conservatively assess the likelihood of any exposure actually causing a loss and the probable cost if it does.

What is your potential downside should adverse events or market activity hit your portfolio? What is the probability of heavy drawdowns? How bad could it get? How much risk are you willing to endure—in the form of volatility—for a given return? Having an idea of the historical probabilities of asset class declines should inform the way a portfolio is structured. It is said that by seeing to your risks, you can let the potential upside take care of itself.

Set a premium that, on average, will deliver a profit after both prospective loss costs and operatingexpenses are covered.

This cannot be emphasized enough—there are risks that pay and risks that do not pay enough to justify taking them.

Concentrated portfolio risk falls firmly into the latter camp. Betting heavily on a small amount of investments is how fortunes are made, but only in hindsight. It doesn’t work out well for the majority of people, but you rarely hear about them. You will hear a lot, always after the fact, about the supposedly brilliant people who made concentrated bets and hit the lottery.

Different asset classes have different risk and return probabilities. Equities return the most over time, but their holders have to go through more duress than investment grade fixed income, for example. Balancing your tolerance for potential losses against your need for future gains is the key to the whole endeavor. In this analogy, your “operating expenses” would be the future liabilities you’ll have in retirement or even sooner if you’re saving for your children’s’ education. Will these operating expenses be covered under a variety of potential market outcomes? Talk to a financial planner if you can’t answer this question on your own.

Be willing to walk away if the appropriate premium can’t be obtained

Some investments offer a lot more risk than what you’d deserve to earn in “premium,” i.e. returns, for your trouble. A recent example would be the MLPs that many investors had been holding in place of where they’d traditionally be buying bonds. For a 7% pass-through dividend yield, investors piled into MLPs. But as oil prices have dropped, the MLPs have on average dropped 40% in the past year, a lost equivalent to six years worth of the dividend income they were chasing.

Investors increasing their current yield by taking credit risk in junk bonds have recently learned a similar lesson. At some point, investors who are conflating high-yielding consumer staples stocks with bonds or who are taking interest rate risk in long-dated Treasurys will see drawdowns as well. So will investors taking counter-party risk via swaps and collateralized debt securities issued by a financial institution.

Bottom line: There’s no free lunch on Wall Street and just about every asset class carries its own form of idiosyncratic risk. Still, there’s nothing wrong with taking risk today in order to earn future rewards. Just make sure you’re being paid for taking it in the form of an adequate potential return. Warren Buffett clearly does. And his returns haven’t been all that bad.