常说，每年8月间股市都运行良好，但与天使相伴的恶魔总时不时出来捣乱。由于投资者对通货紧缩或经济再次萧条抱有极度紧张的情绪，他们也开始担心股市在今年8月的表现。
8月是一个奇怪的月份，很多公司高管、金融机构负责人还有政府领导都忙着度假去了。如果此间没有太惹人不安的消息，股市一般在大队精英人马外出的情况下会随波逐流到一个高位。但此时若出现一个使股市下跌的事件，那么则会引起市场的轩然大波。
1998 年8月，俄罗斯出现债务违约，道琼斯工业平均指数暴跌15%，而在8月以前亚洲金融危机的冲击下，道指已下跌了7%。1990年8月，伊拉克入侵科威特， 道指下挫10%。2005年8月，美国遭遇卡特里娜飓风，道指跌1.5%。股市也曾在美国1987年大崩盘来临之前在8月登上至高点，然后一路俯冲至10 月的低谷。
公司第二季度财报基本已发布完毕，很多公司将其它声明的公布日期推迟到美国劳动节（9月1日）之后。预先安排好的新闻活动要少 于往常。8月股市交易量一般也较小，这会放大任何突发事件带来的影响。美国堪萨斯州资产管理公司Waddell & Reed Financial Inc.首席执行长赫尔曼（Henry Herrmann）称，今年笼罩股市的快钱和短期交易氛围更浓于以往。
传闻已经开始了，只待击破。有人说政府在11月国会中期选举之前可能会实施更多的经济刺激措施，目的在于帮助更多“负资产房主”进行抵押贷款融资，这一传言在上周得到官方否认之前充斥于房屋抵押市场。
即便没有“天降大事”于股市，投资者表示有三个让他们焦虑的问题，主要集中在受创的美国消费者、中国和美联储。
克莱恩托普(Jeffrey Kleintop)说，“消费者问题是目前投资者的一大心病”。市场对于上周五美国发布的7月就业报告的回应恰恰反映了这个问题。周五报告发布后，道指应声大跌，之后有所回升，收盘跌21.42点，至10653.56点。
消费者支出可以代表美国三分之二的经济活动状况，由于政府经济刺激计划快要到期，消费者支出增幅有所减缓。继上周五美国就业报告出炉后，投资者关注的焦点将集中在两大类相关数据上：每周失业数据与每周连锁店销售报告。
连锁店报告将对返校购买季的购买能力给出明确信号，对于零售商来说，这是圣诞节之后第二大重要信息。任何有关就业岗位、销售数量、刺激消费措施或买房数据的走软都会使人们更加担心通货紧缩或经济的二次探底。
美联储最近召开的会议对股市产生的影响都小于往常，但现在突然也成为大家担心的一个焦点。在一系列新出炉报告的刺激下，周二联储会议议题是利率政策，即考虑其它刺激金融体系的方式方法。
圣 路易斯联邦储备银行行长布拉德（James Bullard）日前进行了一项颇为大胆的研究，随后人们开始推断中央银行恢复债券购买行为的可能性有多大，央行购买债券可为金融公司注入新的货币。如果 美联储并没有宣布新的债券购买措施，投资者将从联储会议的会后声明里寻找其可能在未来采取该措施或其它计划的蛛丝马迹。即使一个小小的有关美联储政策变化 的暗示都将会对股市产生影响。
投资者的第三大忧虑来自中国──很多人认为的世界经济发展的第一推动力国家。7月股市表现如此强劲的一个原 因是大家愈发相信中国在未造成任何衰退的前提下成功降低了过热的经济发展速率。任何有关中国经济没能成功软着陆以及中国或许将进一步收紧市场和经济的意见 都会引起人们的担忧。
还有其它一些悬而未决、使投资者紧张的问题是：奥巴马政府如何延长小布什实行的税减方案以及欧洲债务危机是否会死灰复燃。很多人认为欧洲问题在8月结束之前不会有大的动向，但是这依然不能抑制投资者的担心。
总体来说，投资者希望经济在下半年能够有所软化，这一期望在股票价格上已经有所体现。绝大多数人都不希望看到而又害怕面对的一个问题就是经济重陷衰退。
根据Bespoke Investment Group公司的统计，过去20年里，夏天对股市而言不是一个好季节。道指在历年6月、8月和9月都出现下跌，仅在7月有所上涨。这是今年道指月度涨幅情况。
但是8月的表现与众不同。过去20年中，有12年的8月道指都为涨势，包括刚刚过去的四年、甚至是有毁灭意义的2008年的8月。数据显示8月道指的平均增幅为负，因为在8月道指下跌的年份里，跌幅之大已超过了上涨年份的涨幅。也正是8月跌幅之深使一些投资者感到恐慌。
Typically, the stock market does just fine in August, but every now and then, the month's evil twin shows up. Given how nervous investors have become about the risk of deflation or renewed recession, they are beginning to worry about which version of August they will get this year.
August is quirky because so many business, financial and government leaders are on vacation. If there is no unsettling news, stocks tend to drift higher with the A Team out of town. But if something makes the market fall, the drop can be a doozy.
In August 1998, when Russia defaulted on its debt, the Dow Jones Industrial Average fell 15%. It was down 7% the August before, amid an Asian financial crisis. In August 1990, it dropped 10%, as Iraq invaded Kuwait. It fell 1.5% in August 2005, when Hurricane Katrina hit. August also was the month when stocks peaked and headed down before the crash of 1987, although the crash itself waited for October.
Second-quarter corporate-earnings reports are mostly done now, and many companies are putting off other announcements until after Labor Day. Scheduled news events are thinner than usual. Stock-trading volume also tends to slack off in August, which can magnify the impact of any sudden development. Even more than usual, the market is in the hands of fast-money, short-term traders, notes Henry Herrmann, chief executive at investment firm Waddell & Reed in Overland Park, Kan.
Rumors already have popped up, only to be shot down. Talk that the government might add incentives ahead of the November election to help more underwater homeowners refinance mortgages raced through the mortgage market before it was denied by administration officials last week.
Even if no random event rises from a tar pit somewhere, investors say they are worried about three issues, which center on the wounded American consumer, China and the Federal Reserve.
'The consumer is the main issue on investors' minds right now,' Mr. Kleintop says. The market's reaction to Friday's report of soft July job-creation reflected that preoccupation. The Dow industrials fell heavily Friday after the report was issued but then rebounded to finish down 21.42 points at 10653.56.
Consumer spending represents two-thirds of U.S. economic activity, and its growth has slowed as the government stimulus package has begun to run out. Following Friday's jobs news, investors will be focusing on two related bits of data: weekly unemployment data and weekly chain-store sales reports.
The chain-store reports will give clear signals about the health of the back-to-school season, the second most important for retailers after Christmas. Any weakness in jobs numbers, sales numbers, consumer-spending measures or home-buying data will reinforce fears of deflation or a double-dip recession.
The Federal Reserve, whose meetings lately have had less impact than normal on stocks, is suddenly a focus of concern as well. The Fed meets Tuesday on interest-rate policy amid a flurry of reports that it is considering additional ways to juice the financial system.
Following a provocative study by St. Louis Fed President James Bullard, speculation has been centering on the possibility that the central bank could resume buying bonds, which would pump fresh money into financial companies. If the Fed doesn't actually announce new bond purchases, investors will scour its post-meeting statement for hints that it might do that or something else in the future. Even a hint of a change in Fed policy could affect markets.
The third big concern is China, the country now widely viewed as the top driver of global growth. One reason stocks were so strong in July was the growing belief that China is succeeding in cooling off its frantic growth rate without provoking a recession. Any suggestion that this isn't the case and that China might have to clamp down further on its markets or its economy would sow worry.
Other issues lingering in the background, making some investors nervous: what the Obama administration will do about extending the Bush tax cuts and whether the European debt crisis might flare up again. Many think Europe's problems are likely to remain dormant until August is over, but that doesn't keep investors from worrying.
In general, investors expect the economy to soften in the second half of the year, and that expectation already is reflected in stock prices. What most people don't expect, but do fear, is a drop back into recession.
Over the past 20 years, the summer hasn't been kind to stocks, according to research firm Bespoke Investment Group. The Dow on average has fallen in June, August and September, posting a gain only in July. That is the pattern so far this year.
But August is unusual. The Dow has risen in 12 of the past 20 Augusts, including each of the past four years -- even the disastrous 2008. It shows an average decline for the month because, in the years when it has fallen, the declines have been big enough to outweigh the smaller gains of the up years. It is the size of the declines that make some investors uneasy.