投資者很容易陷入兩種截然相反但同樣嚴重的恐慌：一是牛市時擔心錯失良機，二是市場波動時擔心虧損。這兩種恐慌與理性決策是零和關(guān)系。你的情緒越被這兩種恐慌主導(dǎo)，你就越不理性。

那么作為投資者，我們怎樣才能達到最高程度的理性？這里有一條建議：不要老是盯著你的股價。

下次當你注意到你買的股票出現(xiàn)了漲跌時，要想想哪些因素可能影響了這一走勢。不同的股市投資者對于時間的概念是不同的。比如有些共同基金和對沖基金的客戶，他們的耐心跟5歲孩子差不多，他們買進賣出股票，只著眼于他們對未來一到六個月的預(yù)期。然而對于一家壽命達幾十年的公司來說，這點時間幾乎可以忽略不計。

有些買家和賣家甚至不是人類，而是計算機算法，它們會根據(jù)一些變量做出反應(yīng)，然而這些變量可能跟你投資的公司的基本面沒有任何關(guān)系。這些玩家的時間概念是毫秒級的。

還有一些人主要根據(jù)圖表走勢買賣股票。他們并非不知道這家公司是干什么的，但他們告訴你，他們根本不在乎這家公司做什么。在他們眼里，這些公司只是一張張圖表，是穿過一條曲線的另一條曲線。

還有一些投資者，他們研究明天看哪部電影的時間都比研究應(yīng)該買哪只股票的時間多。有些股民在網(wǎng)上看了一篇文章，心血來潮就買了一只股票。還有很多股民買什么股票取決于朋友的推薦。

被動投資的風(fēng)險

我們講，不要老是盯著你的股票看，這并不完全等同于最近正火的一個概念——被動投資。這個問題需要我們展開解釋一下。

利率是折現(xiàn)率（又稱必要收益率）的基礎(chǔ)。折現(xiàn)率是指投資者將未來的現(xiàn)金流轉(zhuǎn)化成當前價值的比率。我們可以認為折現(xiàn)率由兩個層面構(gòu)成：一是基礎(chǔ)層，或者說無風(fēng)險利率（比如10年期國債的利率）；二是風(fēng)險層，它可以補償額外的特定資產(chǎn)風(fēng)險。

在經(jīng)濟大蕭條期間，各國央行通過購買數(shù)萬億美元的政府債券和企業(yè)債券，人為地改變了貨幣價格。相比之下，前蘇聯(lián)的那一套計劃經(jīng)濟簡直就是小孩子的把戲。在好幾十個所謂“自由市場國家”里，央行沒有像前蘇聯(lián)央行那樣干預(yù)鞋子和糖果的價格，而是干預(yù)了最重要的商品——無風(fēng)險利率的價格，而它是大多數(shù)經(jīng)濟決策的核心，也決定了所有資產(chǎn)的估值。

有些公司未來需要等很久才能獲得收益，利率下降對于它們的估值十分有利。對于增長得不那么快、而且收益相對集中于中近期的公司，它們的估值就享受不到這種好處了。

債券市場的動態(tài)也是類似的。短期債券（類似于價值型股票）受利率下降的影響比長期債券（類似于增長型股票）要小得多。

隨著利率受抑制的影響在市場上擴散，那些在選股上哪怕稍有節(jié)制的主動型經(jīng)理人，都會發(fā)現(xiàn)自己的業(yè)績落后于基準，甚至有可能被炒了魷魚。而客戶資金則流向那些不加選擇地買入指數(shù)中的股票的指數(shù)基金。

你可能會問，指數(shù)里都有什么？如今最受歡迎的指數(shù)都是基于公司的市值構(gòu)建的。因此，近期表現(xiàn)越好的公司（比如Facebook、蘋果、Netflix、谷歌等）就越容易獲得更多的新資本——實際上，這四家公司已經(jīng)占了標普500指數(shù)的10%左右。因此，所謂“高存續(xù)期”的公司既享受了低利率的好處，又從指數(shù)中“悶聲發(fā)大財”了。

2018年持有長期債券的投資者可能已經(jīng)發(fā)現(xiàn)，利率上升有時會帶來負面影響。我們現(xiàn)在還不知道下步的利率走向。但是現(xiàn)如今，美國經(jīng)濟增長率達到了近5%（通脹調(diào)整前），美國政府卻背了上萬億美元的財政赤字。那么，到經(jīng)濟衰退時，一旦經(jīng)濟增長放緩或出現(xiàn)負增長，赤字又會變成多少？更糟糕的是，美國已經(jīng)背了21萬億美元的債務(wù)，過去10年間，美國債務(wù)規(guī)模翻了一番，而政府利率支出卻沒有變化（這要感謝低利率）。未來，利率提高甚至大幅提高也并非沒有可能。

如果你持有的是標普500指數(shù)基金（或者長期債券），那么你潛意識里八成認可以下幾條中的某一條：一、利率上升的可能性為零或為極小；二、我能及時脫身；三、我家里供著基金大亨約翰·博格爾的塑像，而且我的時間概念是非常非常長的。

記住：你是股東

再來說說影響了你投資決策的那些人。如果你是一個基本面投資者，那么你買的不僅僅是股票，而是這家企業(yè)的一部分所有權(quán)。

你可能會花幾百個小時做研究，比如看看這家公司的財報，訪問一下它的管理層、競爭對手、客戶和供應(yīng)商。你也可能會建立一個財務(wù)模型，看看它未來幾年的走勢，再做個估值，并且預(yù)測一下哪些因素可能扼殺這家企業(yè)。

如果你把這些都做了，還每天坐在電腦前盯著股價走勢一天幾漲幾落，這就表明，你還是覺得一家公司的價值應(yīng)該由計算機算法決定，由那個只會看圖表卻連你的公司名字都不寫的家伙決定，由隔壁老王決定，由一個智商約等于萬圣節(jié)大南瓜的ETF基金決定。（此處我并不想針對所有的南瓜。）

簡而言之，你花在看股價走勢上的時間越少，你就會越理性。（財富中文網(wǎng)）

本文作者維塔利·凱瑟尼爾森是投資管理協(xié)會有限公司（Investment Management Associates, Inc.）的首席執(zhí)行官、注冊金融分析師。他經(jīng)常在ContrarianEdge.com網(wǎng)站上撰寫有關(guān)股市的文章。他也是Wiley出版社出版的《橫向市場小手冊》(The Little Book of Sideways Markets)一書的作者。

譯者：樸成奎

Investors are prone to two opposing but equally debilitating fears: the fear of missing out when times are good, and the fear of loss when markets are volatile. These two fears have a zero-sum relationship with rational decisions. The more you are dominated by these fears, the less rational you are.

So what can we do, as investors, to move toward maximum rationality? Here’s one piece of advice: Don’t constantly watch your portfolio.

Next time you notice the price of a stock you own moving up or down, think about the factors that may be influencing that move. Stocks are owned by people who have very different time horizons. You’ll have mutual funds and hedge funds whose clients often have the patience of five-year-olds. They are getting in and out of stocks based solely on what they expect them to do in the next month or six months – a rounding error of a time period in the life of a company that lasts decades.

Some buyers and sellers are not even humans but computer algorithms that are reacting to variables that have little or nothing to do with fundamentals of the company you invested in – these players have a time horizon of milliseconds.

You will also have folks who are buying and selling a stock based on the pattern of its chart. Not that they don’t know what the company does; they will tell you they don’t care what it does. For them it’s just a chart with one squiggly line crossing another squiggly line.

Then there are folks who spend more time researching the next movie they are going to see than the stock they’re about to buy. Some of them buy a stock after reading a single article on the internet, while many others buy on the advice of their brilliant neighbor Joe, the orthodontist.

The active dangers of passive investing

Deciding not to constantly look at your portfolio is not necessarily the same thing as embracing the latest craze – passive investing. This one is a bit personal and requires a small detour.

Interest rates are the foundation of the discount rate (also known as the required rate of return) that investors use to convert future cash flows into today’s dollars. Think of the discount rate as being composed of two layers: the foundational layer, or the risk-free rate (the interest rate, let’s say, on the 10-year Treasury); and a risky layer that should compensate you for additional, asset-specific risks.

During the great recession, when central banks artificially changed the price of money by buying trillions in government and corporate bonds, they made the Soviet planned economy look like child’s play. Instead of messing with kiddie stuff like setting prices on shoes and sugar like Soviet central planners did, a few dozen “free market” central bankers set the price of the single most important commodity, the risk-free rate, which is at the core of most economic decisions and the valuation of all assets.

Valuation of companies whose earnings lie far, far in the future benefits dramatically from falling interest rates, while the valuation of companies whose earnings are not growing as much and are concentrated in the present and near future doesn’t enjoy that benefit.

A similar dynamic happens in the bond market: Bonds with short maturities (similar to value stocks) are impacted a lot less by declining interest rates than long-term bonds (similar to growth stocks).

As the impact of suppressed interest rates rippled through the markets, active managers that had even a modicum of discipline in their stock selection found themselves trailing their benchmarks and even getting fired, while customer money flowed into index funds that indiscriminately buy what is in the index.

What is in the index, you may ask? Most popular indices today are constructed based on companies’ capitalization. Thus, companies that have done well lately (for example, the tech giant “FANGs”–Facebook, Apple, Netflix and Alphabet’s Google), get a much greater portion of new capital – in fact the FANGs account for about 10% of the S&P 500 Index. So “high-duration” companies are benefiting from both low interest rates and the “dumbness” of the indices.

However, as investors who hold long-term bonds in 2018 are discovering, rising interest rates can hurt. We don’t know what interest rates will do in the future. But today the U.S. government is running a trillion-dollar budget deficit at a time when the economy is growing at a rate of almost 5%, before adjusting for inflation. What do you think the deficit is going to be when growth slows down or turns negative during a recession (yes, those things do happen)? To make things worse, these deficits add to the $21 trillion of U.S. debt, which doubled over the last 10 years while the government’s interest payments didn’t change (thanks to low interest rates). Higher, maybe even much higher, interest rates are not unlikely going forward.

If you own the S&P 500 (or long-term bonds), you implicitly think one of several things is true: (1) Interest have a zero or insignificant probability of going up; (2) I’ll be able to get out in time; or (3) I have a life-sized statue of John Bogle in my living room, and I have a very, very, very long time horizon.

Remember: You’re an owner

Back to various actors who are responsible for daily ticks of your favorite stocks. If you are a fundamental investor, you are not just buying stocks, you are buying fractional ownership in businesses.

You spend hundreds of hours on research, you read company financial reports; you talk to management, competitors, customers, suppliers. You build a financial model that looks years into the future to value a business, and also to predict what could kill it.

If after you’ve done all that, you still find yourself glued to the computer screen watching the price change tick by tick, you are basically giving credence to the idea that what a company is worth should be decided by algorithmic funds, the guy who reads charts but cannot even spell the name of your company, Joe the neighbor, and an ETF with the IQ of a Halloween pumpkin. (I don’t want to insult everyday pumpkins here.)

In short, the less time you spend looking at your portfolio, the more rational you are going to be.

Vitaliy Katsenelson, CFA, is the CEO at Investment Management Associates, Inc. He writes about the markets at ContrarianEdge.com, and is the author of The Little Book of Sideways Markets (Wiley).