不管投资前做了多少研究，等到交易时总还是多少需要一点信心。人们可能会嘲笑分析师的预测落空，但很多分析师尽管并没有受到公司的压力来粉饰预测，有时还是会失准。研究只能帮到你这么多。接下来需要的是猜测。

    鲜有股票能比亚马逊（Amazon）更加依赖猜测。这家公司在发布数据或指标时堪称小气。亚马逊卖出了多少部Kindle？这家公司不愿透露。它公布假日季的发货量，但只限高峰日数据，不是整个假日季。亚马逊网络服务部门每年将赚取约38亿美元收入，但该公司不会把这一块独立拿出来统计，几年来一直是纳入“其他收入”项目。要弄清楚这个部门的利润率，挑战就更大了。

    诚然，亚马逊也提供业绩指导区间【尽管像Facebook等其他公司最近几个季度都闭口不谈业绩指导值】，但它提供的区间相当宽，宽到连UPS的送货卡车也能轻松驶过。亚马逊这个季度会公布营运利润或亏损吗？不错。据该公司称，本季度收益数据将介于亏损3.40亿美元至盈利1,000万美元之间。这样的靶子，闭着眼睛都能投中。

    缺乏清晰明确的信息让依赖基本面的投资者面临艰难选择：要么干脆不投资亚马逊的股票，要么完全相信公司管理层能把事情做好。选择后者的人近年来投资业绩不错。亚马逊股价在过去5年中飙升了234%，同期标准普尔500指数（S&P 500）仅上涨了15%。

    亚马逊要求投资者在其他方面相信公司的管理层。这家公司从不派息，坚称：“我们想保留全部收益，为未来的增长提供资金。这也意味着亚马逊持续保持低利润率，有时扩张投入得多了，还会出现亏损。但亚马逊收入的持续增长已经为它赢得了信赖。

    但有时，亚马逊也会让看涨的投资者陷入尴尬。亚马逊一直强调自由现金流才是衡量公司健康状况的关键财务数据，而不是很多投资者认为的标准衡量指标——每股收益。自由现金流基本上是企业创造的、超出需要保持其增长所需的那些现金。亚马逊认为，这个指标能更好地衡量亚马逊将利润回报给顾客（而不是投资者）的策略是否成功。

    问题是，亚马逊自由现金流的增长在过去12个月下降到了1.77亿美元，同比骤减85%，主要是因为亚马逊为西雅图的新办公楼支付了14亿美元。但在自由现金流放缓的同时，收入增长也在放缓：上一季度收入同比增长1%，低于之前一个季度的5%和上年同期的12%。

    No matter how much research is done before an investment, there always remains a little bit of faith when it comes time to place a trade. People may mock analysts when their forecasts are off, but the analysts who aren't pressured by their firms to dress up estimates -- which is a lot of them -- still miss the mark sometimes. Research only takes you so far. After that it's only guesswork.

    Few stocks involve more guessing than Amazon (AMZN). The company is tightfisted when it comes to disclosing data or metrics. How many Kindles has Amazon sold? The company won't say. It discloses holiday shipments, but only on the peak day and not for the entire season. Amazon Web services will make an estimated $3.8 billion in revenues a year, but the company won't break it out as its own category, lumping it in with "other revenue" where it's been for years. Figuring out the division's profit margins is even more of a challenge.

    When it comes to guidance, Amazon does offer it (while others like Facebook (FB) have been mute on guidance in recent quarters), but it usually offers a range you could drive a UPS truck through. Will Amazon post an operating profit or a loss this quarter? Yes. According to the company, the figure will land somewhere between a loss of $340 million to a profit of $10 million. That's a dartboard any monkey could hit.

    The lack of clarity leaves investors who rely on fundamentals with an uneasy choice: either don't invest in Amazon's stock or simply trust the management that it will manage things well. Those who've opted for the latter have done pretty well for themselves. Amazon's stock is up 234% over the past five years, while the S&P 500 (SPX) is up 15%.

    Amazon asks investors to trust its management in other ways. It has never paid a dividend,asserting that, "We intend to retain all future earnings to finance future growth." That also means Amazon consistently has thin profit margins and sometimes slips into a loss when it's spending heavily on that future growth. But it's earned trust because it has so consistently delivered on growth in revenue.

    But it can sometimes put Amazon bulls in an awkward position. The company has always stressed free cash flow as the key financial metric to measure its health, instead of the earnings per share that is the standard gauge for many investors. Free cash flow is basically the cash the business is generating beyond the spending needed to keep growing. Amazon feels it's a better measure of whether Amazon's strategy of returning profits to customers (and not investors) is succeeding.

    The problem is, the growth in Amazon's free cash flow over the past 12 months fell to $177 million, an 85% drop from the comparable period a year earlier. That's primarily because Amazon paid $1.4 billion for new offices in Seattle. But free cash flow is slowing at the same time revenue growth is: Revenues in the last quarter grew 1% on year, down from 5% in the previous quarter and 12% in the year-ago quarter.

    亚马逊有所改善的是另一项投资者看重的财务指标：毛利润率，它从一年前的24%增至25.6%。这意味着亚马逊的收入增速快于核心运营成本，而且过去的支出似乎已经开始发挥作用。

    究竟是哪种情况？毛利润率增加，表明亚马逊业务兴旺？还是，收入和自由现金流下降，表明该公司正在遭遇一些阻力？毫不奇怪，看涨者指向前者，看跌者指向后者。因此，亚马逊也仍然是科技行业中投资者分歧最大的公司之一。

    亚马逊正在亚洲和欧洲积极投资拓展业务，但在亚洲遭遇了强大的竞争对手阿里巴巴（Alibaba）。亚马逊还在投资原创TV节目，与Netflix和Hulu竞争。另外，它还在提升亚马逊Prime客户享有的权益，回报客户忠诚度。所有这些计划听起来都不错，有望推动未来几年更加强劲的增长。

    自从亚马逊公布业绩以来，该股股价已下滑6%，表明当前看跌者占据了上风。如果投资者能更加清晰地获悉该公司的业务经营状况，它将有助于缓解担忧并给投资者以回报。就算不能派息或提高净利润率，提供更多的数据也能让他们为自己的信心找到理由。

    亚马逊可能即将进入收入增长放缓、资本开支增加的时期。不管怎样，笃信者仍在继续持有亚马逊股票，长时期低估杰夫•贝佐斯肯定要失算。

    本文作者凯文•凯勒希尔常驻旧金山湾区，撰写金融和科技领域的文章。

    Where Amazon is gaining is in another financial metric favored by its investors: gross margin, which grew to to 25.6% from 24% a year earlier. That means Amazon's revenue is growing faster than its core operating costs, and that previous spending appears to be paying off.

    But which is it? Are rising gross margins signs that Amazon is thriving? Or are declining revenues and free cash flow signaling that it's hitting some headwinds? Unsurprisingly, the bulls are pointing to the former, and the bears are pointing to the latter. So Amazon remains one of the most divisive stocks in the tech sector.

    Amazon is spending aggressively to expand in Europe as well as Asia, where it faces aformidable competitor in Alibaba. It's investing in original TV programming to compete against Netflix (NFLX) and Hulu. And it's adding to Prime benefits to reward customer loyalty. All of these plans are sound and could lead to stronger growth in coming years.

    Amazon's stock has declined 6% since it reported its earnings, suggesting the bears have a stronger case for now. A little more clarity in how its business is working would help alleviate those fears and reward investors, if not with dividends or high net profit margins, then with more data to help them justify their good faith in the company.

    Amazon may be heading into a period of slower revenue growth and higher capital spending. Nonetheless, the company's believers are sticking with the stock, remembering that it's never paid for very long to underestimate Jeff Bezos.

    Kevin Kelleher is a writer covering finance and technology in the San Francisco Bay Area.