市的疯狂波动把投资者的信心撕个粉碎。现在有些人认为， 是时候接受混乱的现实，并采取更加积极主动的交易策略。
“趋势投资”（依据对市场走向的技术分析来买卖股票）的拥护者表示，这种投资方式 不但能帮投资者把握不稳定的市场动向，而且还能在股价下跌时避免巨大的损失。
当前，市场对美国经济复苏能力和未来消费者支出的担忧与日俱 增，这种策略正赢得越来越多投资者的青睐。
不过，趋势投资是颇受争议的。与传统的投资理念不同，传统的投资理念认为，在市场中的长线投 资，而不是短线炒作能为投资者带来最大的成功机会。
对趋势投资者来说，买入持有的投资理念──即根据基本面分析选择股票品种并持有数月或 数年之久──在如今的市场中没有立足之地，只会招来失败的下场。
“你得知道自己在玩什么游戏，你的对手是一群吃人不吐骨头的鲨鱼。” 德克萨斯州Kenjol Capital Management总裁兰德格拉夫(Kenny Landgraf)说，“你可能相信买入持有的投资理念，但市场中有些大玩家并不相信。”
兰德格拉夫使用公司自己开发的一个模型来决定何 时入市，并通过买卖交易所交易基金(ETF)来进行操作。
截止到2010年7月中旬，该公司处于满仓运作状态，他们是在6月中旬重新入市 的。兰德格拉夫介绍道，趋势投资的最大好处在于可以避免重大损失。“(在开始满仓投资后)，你会始终趋向一个更具防御性的仓位，直至选择离开。”
趋 势投资策略以自己的表现证明，其在最困难的市场环境中也能行之有效。
2008年8月， 兰德格拉夫通知“板块轮换”(Sector Rotation)投资组合──该公司的全美股产品──的客户，该组合要清盘退市，之后又经历了“一两次失败的重新入市”，直到2009年3月12日才彻 底回归。
这一投资策略使得该投资组合2008到2009两年的年化投资回报率实现1.5%的正收益，而同期的标普500指数 (Standard & Poor's 50)下跌了11%
此外，投资研究机构晨星公司(Morningstar Inc.)提供的数据显示，在此期间，总计2,301只美股共同基金中，只有63只能实现正回报，仅占不到3%的比重。
一些专业化的股票 共同基金正是利用了趋势投资的理念。
晨星公司的数据显示，基金Stadion Managed Portfolio在2008年仅损失了5.8%。该基金投资于一系列ETF，在2007年11月退出市场，直至2009年4月中旬才重新达到全额投资的 状态。
如今，该基金又彻底清空了股票，而且从5月初就已如此。
资金管理公司Stadion Money Management的首席投资长汤普森(Brad Thompson)表示，他们的方法能为投资者提供“一种轻松得多的股市体验”。
不 过，尽管Stadion公司和Kenjol公司的投资策略都成功避开了2008年最糟糕的时刻，但它们也都错过了第二年市场复苏中的很大一部分。
Kenjol 公司的“板块轮换”组合2009年的净值增长为24.3%，同期的标普500指数上涨了26.5%，而Stadion公司的年度回报率只有区区2.7%。
Kenjol 公司并没有提供2010年至今的收益情况，但Stadion公司的基金截至7月15号的净值增长为2.5%，超过标普500指数三个百分点。
考 普林(Wayne Copelin)是德克萨斯州公司Copelin Financial的创始人，他说过去十年来的两次熊市已经让他确信，买进持有策略已经不再适合如今的股市。
“多年来，资产管理机构一直都在宣传‘与其预测市场走势，不如相信时间’，但我们最终发现，他们之所以这么说，是让投资者始终保持全额投资，他们就可以始 终保持有钱可赚，” 考普林这样说道。
Volatile stock markets have left investor confidence in tatters. Now, some say it is time to accept the turmoil and adopt more-dynamic trading strategies.
Proponents of 'trend' investing -- buying and selling stocks depending on technical analysis of the market's direction -- say the tactic not only enables investors to navigate unstable markets, but also prevents big losses when prices fall.
This stance is winning converts at a time when concern about the strength of the U.S. economic recovery and the future of consumer spending is running high.
Yet this technique is controversial, as it counters conventional wisdom that time in the market, not market timing, offers individual investors their best chance for success.
To trend followers, the notion of buy-and-hold investing -- picking stocks based on fundamentals and keeping the investments for months or years -- has no place in today's market and, in fact, is a recipe for defeat.
'You have to understand the game you're playing; you're playing with sharks,' said Kenny Landgraf, president of Kenjol Capital Management in Austin, Texas. 'You may believe in buy and hold, but there are large players out there that don't.'
Mr. Landgraf uses a proprietary formula to decide when to invest, and approaches the market using exchange-traded funds.
As of this past week, the firm was fully invested, having jumped back into the market mid-June. The main advantage of trend investing is protection from heavy losses, Mr. Landgraf said.
'[After starting fully invested] you're constantly moving to a more-defensive position until you just get out,' he said.
The strategy has shown it can work under the most difficult circumstances.
Mr. Landgraf took clients in his Sector Rotation portfolio, his firm's all-U.S. stock offering, out of the market in August 2008, and after 'one or two false starts' didn't venture back until March 12, 2009.
This approach gave the portfolio an annualized gain of 1.5% for the two years from 2008 and 2009. By contrast, the Standard & Poor's 500-stock index was down 11% over that period.
Moreover, data from investment-researcher Morningstar Inc. show that less than 3% of stock mutual funds, just 63 out of 2,301, were in the black.
Trend investing underpins a few specialized stock mutual funds.
Stadion Managed Portfolio (trading symbol: ETFFX) lost just 5.8% in 2008, according to Morningstar. The fund, which invests in an array of exchange-traded funds, pulled its money from the market in November 2007 and didn't fully recommit until mid-April 2009.
Nowadays, it is completely out of the market, and has been since the beginning of May.
Stadion's approach offers investors 'a much more comfortable ride' said Brad Thompson, chief investment officer at Stadion Money Management.
Yet while both Stadion's and Kenjol's strategies sidestepped the worst of 2008, they also missed much of the recovery the following year.
Kenjol's Sector Rotation was up 24.3% in 2009 compared with a 26.5% gain for the S&P 500, while the Stadion fund gained only 2.7%.
Kenjol didn't provide returns for this year, but Stadion's fund was up 2.5% as of July 15, three percentage points better than the S&P 500.
Wayne Copelin, founder of Copelin Financial in Sugar Land, Texas, said two bear markets in the past decade have convinced him that a buy-and-hold strategy can't work in today's markets.
'We've heard for years from money managers the pitch that 'it's not about timing but time in the market,' but then you notice that the ones pitching this are the ones that make money if you stay fully invested,' said Mr. Copelin.