可能扼杀Facebook股价上涨行情的4大因素

    一年前，鲜有投资者看涨Facebook。有些文章的作者甚至认为，23美元的股价仍然有水分。其他人则认为，玛丽莎•梅耶尔执掌的雅虎（Yahoo）更有希望扭转不利局面。此后虽然有些看跌者开始缓和悲观看法，但普遍观点是，Facebook估值过高，具有投机性。

    过去的一年中，Facebook股价涨了115%，而纳斯达克综合指数仅上涨了37%。市场调研公司Thomson/First Call跟踪的40位证券分析师中，目前有32位给予这只股票“买入”或“强力买入”评级，8位分析师给予“持有”评级，没有一位给予“卖出”评级。即便大幅反弹之后，目前该股的空头头寸只有一年前的1/3。

    到底是什么发生了变化？造成Facebook股价大逆转的主要原因是它移动广告的突然增长。当初，这只股票的股价还在20多美元区间内徘徊时，Facebook就瞄准了受众从桌面电脑转向移动设备的趋势，准备从中掘金。它聚焦移动的努力获得了成效。一年前，它的收入增长率只有32%。截至9月份的最近季度，它的收入增长了60%。

    但最近几周，有些迹象表明，Facebook的大幅反弹开始失去了动力。上周，这只股票曾下探到45.73美元，较1个月前创下的54.82美元纪录高点下跌了17%。本周一，它在47美元上下交易。这是下跌的前期信号，还是短暂走弱？展望未来，值得考虑的问题是，什么因素可能结束Facebook这一轮反弹。

    Facebook的业务改善已体现在股价中。这家公司的复苏十分显著，导致人们对它的期望值高得有些离谱，甚至比它去年5月上市的时候还要高。这些使得Facebook的估值非常高，就连未来几年尚未发生的增长也已经计入股价。Facebook当前股价是它过去12个月每股收益的125倍，是2014年预计每股收益的44倍。

    还有其它几个因素将推动Facebook增长：广告的受众投放更加准确，为广告主提供更佳回报；将开始在Instagram和Facebook视频上卖出更多广告；能建立一个更强大的第三方广告网络；广告主对Facebook广告的需求当前没有显现出任何放缓的迹象。这些是乐观的预期，但这也是众所周知的事情，不能为这只股票继续走高提供支撑。

    Facebook将再次出现增长率下滑的现象。分析人士预测，Facebook 公司2013年收入增长50%，2014年增长36%。这还是在上述所有的增长动力推动之下。但所有这些都取决于一个答案非常不确定的重要问题：Facebook还能向移动端注入多少广告、同时又不会把用户赶跑？

    Facebook首席财务官戴维•埃伯斯曼在上次业绩电话会议中表示，公司“显著”增加了电脑版广告，“适度”增加了移动端广告。它计划将广告内容保持在移动端信息流内容的5%左右，依靠使用量增长和需求增加来保持增长。

    A year ago, few investors were bullish on Facebook (FB). Some writers argued that, at $23 a share, it was still overvalued. Others thought Yahoo (YHOO) under Marissa Mayer had a better shot at a turnaround. While some bears were beginning to temper their pessimism, the consensus view was that Facebook was expensive and speculative.

    In the past year, Facebook's stock has risen 115%, against a 37% rise in the Nasdaq Composite Index. Of 40 securities analysts tracked by Thomson/First Call, 32 currently have a buy or strong buy rating, 8 have a hold rating and none have a sell rating. Even with the rally, short interest on the stock is a third of what it was a year ago.

    What changed? The main reason for this reversal of fortune in Facebook's stock is the company's sudden growth in mobile ads. Back when the stock was languishing in the $20 range, Facebook vowed to monetize its audience's shift from desktop computers to mobile devices. That focus on mobile worked. A year ago, revenue was growing at only 32%. In its most recent quarter September, revenue grew 60%.

    In the last few weeks, however, there have been a few signs that Facebook's impressive rally is running out of steam. Last week, the stock traded as low as $45.73, or 17% down from its record high of $54.82 one month ago. The stock was trading around $47 a share Monday. Is this decline an early sign of a downturn or just a quick sputter? Looking ahead, it's worth considering factors that could derail the Facebook rally.

    Facebook's turnaround is priced into its stock. The company's recovery was so impressive it paradoxically set the bar of expectations higher even than it was when Facebook went public in May of last year. That has left Facebook very expensive, priced for growth that won't happen for a couple of years: Facebook is trading at 125 times its trailing 12-month earnings, and at 44 times its estimated earnings in 2014.

    There are still several factors that will drive Facebook's growth: the company is better targeting its ads to deliver stronger returns for advertisers; it will start to sell more ads on Instagram and on Facebook videos; it can build a stronger third-party ad network; and advertiser demand for Facebook ads is showing no signs of slowing right now. That's a sunny forecast, but it's well known. It doesn't justify the stock moving higher from here.

    Facebook will see growth rates decline again. Analysts are forecasting 50% growth in Facebook revenue for 2013 and 36% for 2014. That's with all of the growth initatives listed above. But all of this hinges on an important question with a very uncertain answer: How many more ads can Facebook load into its mobile feeds without driving away users?

    In Facebook's last earnings call, CFO David Ebersman said the company "significantly" increased desktop ads but "modestly" increased those in mobile feeds. The company plans on keeping ads at around 5% of mobile-feed content, relying on growing usage and rising demand to maintain growth.