Lisa Smith 2016年9月27日
擇時交易是試圖預測未來市場運動的方向以便能進行低買高賣。這是一個許多專業投資者使用並且大多數其他投資者希望複制的策略。有趣的是，這個策略對許多交易者來說也帶有消極含義。你是否曾經想過當一個日内交易員賺錢呢？請繼續閱讀我們關於這個策略的讨論。
争議
在學術層面上，擇時交易受到那些相信有效市場理論的人質疑。有效市場理論的前提是在任何時間，單一股票或者市場的價格完全反應所有當前信息。因此，由於沒有人能優先於其他人獲得信息，所以沒有投資者能獲得預測回報的優勢。
在學術界以外，擇時交易的争議主要集中在日内交易的執行是由散戶投資者進行的，2003年對沖機構投資者爆出了對沖基金醜聞。這類問題的媒體報道已經非常普遍，以至於許多投資者認為日内交易不是一個可靠的投資策略。因為大衆媒體的投資者關註度比學術媒體大很多，擇時交易在大衆媒體中的形象提供了一個很好的關於這個話題探索的主題。
日内交易站在了傳統交易哲學“買入並持有”的對立面。它是一個終極市場時機把握策略。雖然日内交易吸引的所有註意力表明這個理論是可以實現的，但是批評者認為如果這個理論成立，至少一個著名基金經理已經掌握這個系統並會出現類似“巴菲特的日内交易”這樣的新聞。
衆多已經成為傳奇的投資者中沒有一個是通過日内交易發家的。即使是使用30分鐘到30天交易時間框架的邁克爾·斯坦哈特也表示在進行投資決定時也需要考慮長期視角。從經濟角度來看，許多專業的基金經理和金融顧問都會回避日内交易，認為回報不能與風險相匹配。
合法性、道德和共同基金醜聞
刨除争議，擇時交易既不違法也不違反道德準則。嘗試獲利是投資者進行投資的原因，選擇你的買賣時機以便能進行低買高賣是大多數投資者的共同目標。
共同基金的問題是他們的擇時交易是暗箱操作的，因為對沖基金公司發佈的招股說明說上嚴格禁止短期交易。盡管存在這一禁令，某些特殊客戶還是被允許這樣做。因此，問題不是出現在交易策略上，而是這一策略不公平和不道德的執行，是因為對客戶的區別對待，允許一些人這麼做而禁止其他人使用相同的策略。
專業的方法
世界上所有偉大投資者的成功都在某種程度上依賴擇時交易。無論他們的買賣交易決定是根據市場的基本面分析、單個公司的技術分析、個人直覺還是所有這些因素，他們成功的最終原因都是在正確的時間做出了正確的交易。在大多數例子中，這些決定的時間都很長而且依賴“買入並持有”策略。
價值投資是一個簡單的例子，因為這一策略基於購買那些價格低於内在價值的股票，並在其價值得到市場承認時出售。大多數價值投資者以耐心著稱，因為價值被低估的股票價值低估的時間通常會維持很長時間。
進行擇時交易還是不進行擇時交易？
如果你的目標是低買高賣，那麼你就是擇時交易者。如上面所說的，短期擇時交易要比長期擇時交易難的多。普通投資者沒有時間（或經歷）觀察每日市場運動，進行長期投資要比判斷每日市場走向要好的多。當考慮到風險和成本，即使是最專業的投資者也更希望盡量延長他們的投資時間週期。無論你持有多久，購買一種投資並持有到價格上漲則比在上午9點買入投資而希望在幾個小時之後獲利要容易成功的多。
Would You Profit As A Day Trader?
By Lisa Smith | Updated September 27, 2016 — 1:13 PM EDT
Market timing attempts to predict the direction of future market movements in order to buy low and sell high. It is a strategy that most professional investors rely on and most other investors hope to replicate. Interestingly, it's also a strategy that has negative connotations for many investors. Have you ever wondered whether you could make money as a day trader? Read on as we cover the controversy behind this strategy.
The Controversy
At the academic level, the very concept of market timing is called into question by those who believe in the efficient market theory. This theory is based on the premise that, at any given time, prices fully reflect all available information on a particular stock and/or market. Thus, no investor has an advantage in predicting a return on a stock price because no one has access to information not already available to everyone else.
Outside of academia, the controversy surrounding market timing is primarily focused on day trading conducted by individual investors and the mutual fund trading scandals perpetrated by institutional investors in 2003. Media coverage of these issues has been so prevalent that many investors now dismiss market timing as a credible investment strategy. Because the popular media has a significantly greater audience among investors than most academics do, the image the popular media has created for market timing provides a good spot to begin an exploration of the topic.
Day trading sits at the extreme end of the investing spectrum from conventional buy-and-hold wisdom. It is the ultimate market-timing strategy. While all the attention that day trading attracts seems to suggest that the theory is sound, critics argue that, if that were so, at least one famous money manager would have mastered the system and claimed the title of "the Warren Buffet of day trading".
The long list of successful investors that have become legends in their own time does not include a single individual that built his or her reputation by day trading. Even Michael Steinhardt, who made his fortune trading in time horizons ranging from 30 minutes to 30 days, claimed to take a long-term perspective on his investment decisions. From an economic perspective, many professional money managers and financial advisors shy away from day trading, arguing that the reward simply does not justify the risk.
Legality, Ethics and Mutual Fund Scandals
Despite the controversy, market timing is neither illegal nor unethical. Attempting to make a profit is the reason investors invest, and timing your purchases and sales so that you buy low and sell high is the general goal of most investors (although short-selling andarbitrage take a different approach, the success or failure of these strategies still depends on timing).
The problems with mutual fund trading that cast market timing in a negative light occurred because the prospectuses written by the mutual fund companies strictly forbid short-term trading. Despite this prohibition, special clients were allowed to do it anyway. So, the problem was not with the trading strategy but rather with the unethical and unfair implementation of that strategy, which permitted some investors to engage in it while excluding others.
The Professional Approach
All of the world's greatest investors rely, to some extent, on market timing for their success. Whether they base their buy/sell decisions on fundamental analysis of the markets, technical analysis of individual companies, personal intuition, or all of the above, the ultimate reason for their success involves making the right trades at the right time. In most cases, those decisions involve extended periods of time and are based on buy-and-hold investment strategies.
Value investing is a clear example, as the strategy is based on buying stocks that trade for less than their intrinsic values and selling them when their value is recognized in the marketplace. Most value investors are known for their patience, as undervalued stocks often remain undervalued for significant periods of time.
To Time or Not to Time?
If your goal is to buy low and sell high, you are market timing. As noted above, it is very difficult to be successful at short-term market timing over an extended period of time. The average investor doesn't have the time (or desire) to watch the market on a daily basis and will be far better served by a focus on long-term investing instead of trying to guess the direction of the market on a daily basis. When the costs and risks are factored into the equation, even most professional investors prefer to stretch their investment horizons over a longer time frame. It is far easier to be successful if you purchase an investment and hold it until the price rises, regardless of how long it takes, than to purchase an investment at 9am and hope to make a profit just a few hours later.
本文翻譯由兄弟財經提供
文章來源：http://www.investopedia.com/articles/trading/07/market-timing.asp?rp=i