比特幣是2019年表現最好的資產之一，自2018年年底以來價格翻了一倍多。但相較于2018年年初，價格仍然下跌了近50％。然而，相比2016年年底，比特幣上漲了近700％。但和2017年12月比特幣狂熱時期的峰值價格相比，下跌超過60％。

自2000年互聯網泡沫達到頂峰以來，標普500的年回報率僅為5.3％。然而，2009年3月以來的年回報率平均超過16％。回到2007年11月，每年的回報率僅為7.3％。然而，再回到1995年，年回報率接近10％，恰恰是長期以來的平均水平。

黃金沒什么起色已經有些年頭了，自2011年觸頂后金價已經下跌30％。但如果相較于2000年年初，黃金價格上漲了360％。然而，自1980年以來，按照通貨膨脹調整后的實際價格計算，黃金其實已經虧損。不過自1971年美國退出金本位制以來，黃金價格年平均上漲近8％。

我可以繼續舉例，但你肯定已經明白了。在你能想到的幾乎每一個證券或資產市場，無論你在辯論中支持牛市還是熊市，都有足夠的彈藥支持你的觀點。因為事實很簡單：市場是周期性的。這意味著你只需要更改起始日期，讓有關數據符合你的立場，就可以贏得有關任何市場的任何辯論。

然而，投資者仍然可以從大漲大落中總結一些經驗：

不要試圖預測峰值和底部

當你引用市場峰值和低谷時的價格數據時，可能感覺這類游戲還挺有趣，但事實上，沒有人厲害到總是能夠抄底，也沒有人倒霉到總是在最高位買入。正如投資者、慈善家伯納德·巴魯克所言：“不要試圖抄底買入或者摸頂賣出。這是不可能的——除非是個騙子。”

市場在大多數時候都處于中間位置，既非在一個周期的頂點附近，也不是在底部周圍。重點是要記住，讓事后諸葛亮來看，市場何時登頂、何時觸底似乎總是更容易判斷。

短期市場走勢更多的是情緒和趨勢作用使然，而非市場的基本面，因此在短期內嘗試預測市場實際上就像猜測人類情緒的走向。我甚至無法預測自己明天早上的情緒，更別說市場上幾百萬投資者的集體情緒了。

買賣多元化

人們常說多元化是金融領域唯一的免費午餐，這種理念可不僅適用于多元化資產配置和投資策略。要想免受預測市場高點和低點的誘惑，可以使用平均成本法，定期進行資產購入和賣出，隨著時間的推移，實現買賣多元化。

按照時間有條理地進行投資不會像等著要大賺一筆時那么興奮，但這么做可以攤平風險，確保你不會在最糟的時刻把所有錢都投進市場。

如果使用平均成本法進行市場定投，你在股價下跌時買入的股票份額更多，上漲時買入份額變少。使用這種策略，你無法把錢全部用來抄底，但當市場觸底或者位于底部附近時，你能買入一些，這就已經超過大多數人了。

停止白日夢

如果你在1997年亞馬遜首次公開募股時買了1萬美元該公司的股票，你知道現在你能有多少錢嗎？數據顯示你將擁有超過960萬美元。但現實表明，你更可能只有3萬美元左右。

互聯網泡沫期間，亞馬遜股價上漲近100倍，之后大幅下挫，跌落回現實，在沖刷期結束時從高點回落近95％。之后即使你有幸以與IPO價格差不多的買入，人性也決定了，你會在看到股價下跌80％后賣出，之后再被腰斬甚至更多。

即使在互聯網熄火之后的低潮，長線選手仍然能夠賺到錢，你的錢將增加到3萬美元左右。但即使那時，大多數投資者也會在遠沒到觸底時全部拋出。

在腦子里玩IPO樂透游戲很有意思，但如果總是夢見找到了那張中獎彩票，對投資者也毫無用處。即使你選對了數字，也很可能無法長期持有，等不到收獲獎金的那一天。

在討論市場時，使用某一特定時期內的精確價格數據作為論據確實是論證觀點的好方法。但實際上，沒有人能夠確保每一次都抄底買入，摸高賣出。（財富中文網）

本·卡爾森是Ritholtz Wealth Management公司的機構資產管理總監。他著有《常識帶來財富：為何在所有投資計劃中簡單比復雜更有效》。

譯者：Agatha

Bitcoin is one of the best performing assets of 2019, more than doubling in price since the end of 2018. Yet from the start of 2018, prices are still down nearly 50%. However, since year-end 2016, Bitcoin is up almost 700%. But from peak prices seen at the height of the Bitcoin craze in December 2017, the price is down more than 60%.

Since the peak of the dot-com bubble in 2000, the S&P 500 has delivered annual returns of just 5.3%. Yet since March 2009, returns are more than 16% per year. Go back to November 2007 and returns are a more pedestrian 7.3% annually. Yet going back to 1995, returns are close to 10% per year, dead on the long-term averages.

Gold has been sucking wind for a number of years now, down 30% since peaking in 2011. But if you were to go back to the start of 2000, gold is up 360%. However, since 1980 gold has lost money on a real, inflation-adjusted basis. Yet since the U.S. went off the gold standard in 1971, the price is up nearly 8% per year.

I could continue but you get the point. There will always be ammunition for both sides of the bull and bear debate in almost every security or market imaginable for the simple fact that markets are cyclical. That means you can win any argument about the markets by simply changing your start or end dates to suite your stance.

There are, however, some lessons investors can glean from these wild swings in price:

Don’t try to predict tops and bottoms

It can be fun to play these games where you cite performance from the absolute peak or trough in price but the truth is no one is good enough to always buy at market bottoms just like no one is bad enough to always buy at market tops. As investor and philanthropist Bernard Baruch once observed, “Don’t try to buy at the bottom and sell at the top. This can’t be done—except by liars.”

Most of the time markets are somewhere in the middle, not approaching a generational top or bottom. And it’s important to remember that market tops and bottoms always look much easier to call with the benefit of hindsight.

Short-term market moves are a function of emotion and trends rather than fundamentals so trying forecast the markets in the short-term is really a function of guessing the direction of human emotions. I can’t predict my own mood tomorrow morning, let alone the collective mood of millions of market participants.

Diversify your buys and sells

It’s often said that diversification is the one free lunch in finance but this idea extends beyond your mix of asset classes and investment strategies. One way to avoid the temptation to predict market highs and lows is to diversify across time in the markets by dollar cost averaging your purchases and sales periodically into and out of your investments.

Methodically investing over time isn’t as exciting as waiting for the fat pitch to put your money to work but it spreads your risk by ensuring you’ll never put all your money to work in the market at the worst possible moment.

Dollar cost averaging a set amount into the market also allows you to buy more shares when stocks are falling and fewer shares when stocks are rising. You won’t invest all your money at the market bottom with this strategy but you will invest some at or near the market bottom which is better than most people can say.

Stop dreaming

Do you know how much money you would have if you would have invested $10,000 into Amazon at their IPO in 1997? The data says you would now have more than $9.6 million. But reality says you would probably have more like $30,000.

After rising nearly 100-fold during the dot-com bubble, Amazon shares came back to earth with a thud, falling almost 95% from their highs by the time the washout was over. Even if you had the good fortune of buying the stock around its IPO price, human nature dictates you would have sold after seeing your stock price fall 80%, and then get chopped in half and more from there.

Even at the lows following the dot-com flameout that still would have been good for a two-bagger, growing your money to around $30,000. But even then, most investors would have sold out well before the bottom.

It’s fun to play the IPO lottery game in your head but it does investors no good to constantly dream about finding that winning ticket. Chances are even if you picked the right numbers, you wouldn’t be able to stick with them over the long haul to collect your winnings.

Using precise price points with specific start and end dates are a wonderful way to make a point when discussing markets. But no one actually makes all of their buys and sells by top-ticking or bottom-fishing in the markets.

Ben Carlson is the director of institutional asset management at Ritholtz Wealth Management. He is the author of A Wealth of Common Sense: Why Simplicity Trumps Complexity in any Investment Plan.