”The stock market appears to be an efficient mechanism that adjusts quite quickly to new information.
Neither technical analysis, which analyzes the past price movements of stocks, nor fundamental analysis, which analyzes more basic information about the prospects for individual companies and the economy, seems to yield consistent benefits. It appears that the only way to obtain higher long-run investment returns is to accept greater risks.“
股票市場似乎有一個效率的機制把資訊即時反應在價格上。
技術分析，分析的是股價在過去的走勢。
基本分析，著重在對個別公司或經濟前景的基本資料。
技術分析和基本分析，都無法產生一致性的投資獲利結果。
似乎在長期獲致更高的投資收益，唯一的途徑就只能多冒一點風險。
”Unfortunately, a perfect risk measure does not exist. Beta, the risk measure from the capital-asset pricing model, looks nice on the surface. It is a simple, easy-to-understand measure of market sensitivity. Alas, beta also has its warts. The actual relationship between beta and rate of return has not corresponded to the relationship predicted in theory during long periods of the twentieth century. Moreover, betas for individual stocks are not stable over time, and they are very sensitive to the market proxy against which they are measured.“
很不幸，風險並沒有完美的衡量方法。
資本財評價模型的Beta值，似乎不錯，它是衡量市場敏感度很簡單易懂的方法。
但是Beta也有它的缺點。從20世紀巿場的長期表現看來，Beta值和報酬率的真正關係，並不像評價模型所預估的那樣。
更重要的是，個別股票的Beta值並不穩定，而且它的數值對衡量的是哪些股票非常敏感。
”I have argued here that no single measure is likely to capture adequately the variety of systematic risk influences on individual stocks and portfolios. Returns are probably sensitive to general market swings, to changes in interest and inflation rates, to changes in national income, and, undoubtedly, to other economic factors such as exchange rates. Moreover, there is evidence that returns are higher for stocks with lower price-book ratios and smaller size. Other factors such as profitability and momentum also appear to play a role. The mystical perfect risk measure is still beyond our grasp.“
我認為沒有任何方式可以適度衡量個股或投資組合所呈現的各種系統風險。
收益的高低或許和總體經濟市場的動盪、利率和通貨膨脹率、國民所得的改變，無疑與其他經濟因素相關，譬如滙率。
更有甚者，有跡象顯示低「股價/帳面價值比率」而且公司規模是小的股票收益會比較高。
至於其他因素，獲利能力和股票的動能，似乎也扮演某種角色。
傳說中的完美風險衡量，目前我們還沒有。
How do you go about buying stocks? Basically, there are three ways. I call them the No-Brainer Step, the Do-It-Yourself Step, and the Substitute-Player Step.
那麼，怎麼買股票呢？
基本上有三種方法：不傷腦筋的股票方法、親力親為的股票法、靠專家投資股票法。
“In the first case, you simply buy shares in various broad-based index funds or indexed ETFs designed to track the different classes of stocks that make up your portfolio. This method also has the virtue of being absolutely simple. Even if you have trouble chewing gum while walking randomly, you can master it. The market, in effect, pulls you along with it. For most investors, especially those who prefer an easy, lower-risk solution to investing, I recommend bowing to the wisdom of the market and using domestic and international index funds for the entire investment portfolio. For all investors, however, I recommend that the core of the investment portfolio especially the retirement portion be invested in index funds or ETFs.”
第一種，不傷腦筋的股票方法，就是去買充分分散市場的指數基金所買的股票，或者直接去買各種類的指數股票型基金(ETF)，來形成自己要的投資組合。
這個方法最大的好處是極為簡單，對股票市場再弄不明白的人，都可以輕易做到。那樣做，就跟著市場的大勢走了。
大部分的投資者，尤其是希望採用方式簡單、風險低的投資方法者，我建議大家臣服市場的智慧，用國內及國際性的指數型基金來充實整個投資組合。
對所有的投資者，我則建議核心的投資組合，尤其是退休金的部位，要投資在比較穩當的指數基金或指數股票型基金(ETF)上面。
“Under the second system, you jog down Wall Street, picking your own stocks and perhaps overweighting certain industries or countries. I recommend that your serious money set aside to provide for a comfortable retirement be invested in a diversified portfolio of index funds. But if you would like to take some extra money you can afford to risk and if you enjoy the game of picking stocks, I’ve provided a series of rules to help tilt the odds of success a bit more in your favor…”
第二種，親力親為的股票法，你自己直接到股票市場中選擇自己要投資的股票。
可以偏向某些產業、國家。
我建議當作退休的重要資金要另外先分開來，投資在風險分散的投資組合或者是指數型基金。
如果你喜歡多投資一些資金在可承受的風險個股，享受選股的樂趣，那麼我將提供一些助你成功的原則供你參考。
“Third, you can sit on a curb and choose a professional investment manager to do the walking down Wall Street for you. Professional advisers can choose the mix of investments best suited for your capacity and willingness to accept risk and ensure that you have the benefits of broad diversification. Unfortunately, most investment advisers are expensive and they often have conflicts of interest. Fortunately, a new breed of low cost advisers is now available. These advisers often use automated technologies to manage diversified portfolios of index funds and they charge rock-bottom fees….”
第三種，靠專家投資股票法。
理財顧問會依你的財力和承擔風險的意願，並保證充份的分散風險，建議最適合的投資組合。只是，一般投資理財的顧問費用都很高，而且他們也會有潛在的利益衝突。
所幸，現在新一代有收費低廉的理財顧問，他們透過自動化科技管理分散風險的指數基金投資組合，收費則是非常非常低…….
“Rule 1: Confine stock purchases to companies that appear able to sustain above-average earnings growth for at least five years.
Rule 2: Never pay more for a stock than can reasonably be justified by a firm foundation of value…Under my rule it is perfectly all right to buy a stock with a P/E multiple slightly above the market average as long as the company’s growth prospects are substantially above average….
Rule 4: Trade as little as possible. “
如果要親力親為去挑選股票做投資，要避開雷區，有三項原則要遵守：
原則1：只投資在收益成長率在未來五年看起來高於(產業)平均值的股票。
原則2：不要付超過基本分析所估的公司價值去買它的股票。買本益本(P/E) 倍數高於市場平均值，而且該公司的成長前景優於市場平均表現的股票。
原則3：避免頻繁買賣進出市場。
……
“A random walk down Wall Street” 這本書，在我唸研究所的時候，教授講述投資學的時候就提到過，主要是說巿場是如此難以捉摸，甚至有人比喻，把股票名稱放在旋轉圓盤上轉動，由𤠣子投擲，中什麼投資什麼，據說獲利不比專家的投資組合還差呢！
投資當然有風險，但是你不理財財不理你，不冒風險投資當然也不會有獲益。
“A random walk down Wall Street” 告訴我們的是，市場高深莫測，但是要避免犯低級的錯誤，就不要買爛股票，不要付太高的價格買好股票。如果難以抉擇，也不要不買股票，至少要買風險已經充分分散的指數型基金，那麼才能分享市場的紅利。
*：Burton G. Malkiel, “A random walk down Wall Street,” 2023, LSC Communications, Harrisonburg
P.S. 什麼是Beta值？
那是衡量個股或投資組合的股價，相對於市場(指數)的波動程度。
假設市場的beta 為1，那麼某個股的beta如果為2，那麼代表市場漲跌10%，該個股漲跌為20%。如果某個股的beta為0.5，那麼代表市場漲跌10%，該個股漲跌為5%。
投資學的理論是，較高beta代表較高的系統風險(非系統風險可透過投資組合分散掉)，必須給投資者較高報酬才會有人投資較高系統風險的股票。這就是「高風險高報酬」的理論基礎。
2023/11/10 A random walk down Wall Street Damakey
