苹果（Apple）承诺回购股票，但它的股价需要涨到多高才能使得回购计划物有所值？这个问题值得一问。毕竟，苹果原本可以将宣布用于股票回购的100亿美元花在其他很多事情上，同样能提升股东的价值，比如，提高已宣布的99亿美元年度派息（苹果当前的股息收益率为1.8%），甚至进行一次性特别派息。

    为回答这个问题，Fortuna Advisors的格里高里•米兰诺进行了一些简单的计算；Fortuna Advisors是一家为财富500强公司提供市值最大化建议的咨询公司。米兰诺认为，股票回购就和公司其他任何投资一样，必须提供良好的回报，才称得上是对资本的合理利用。换句话说，如果一家公司按每股10美元的价格回购股票，第二年股价涨至12美元，给股东带来的“投资回报率”就是20%。由于企业平均资本成本为每年10%（债务和股东权益费用），如果想增加股东利润，大部分公司回购的回报率应超过10%。

    苹果的情况是其资本回报率异常高。这家科技巨头的经营资本回报率约为40%，远远高于其资本成本。那么，苹果回购股票的最低投资回报率应当是多少呢？米兰诺认为，20%的“投资回报率”是一个合理的数字。

    如果这次回购要达到这样的回报率，米兰诺称，未来五年苹果股价须上涨128%至1,368美元。如果是较低一些的10%回报率，苹果股价则需要在五年内涨至984美元。

    苹果股价能达到这么高的水平吗？当今的苹果可谓占尽天时地利人和。过去一年，该股股价上涨了82%。仅第一季度，受iPad、 iPhone销售火爆推动，苹果就已经实现了160亿美元的自由现金流。但在股票市场，诸事难料。“股价涨到800美元就和跌到500美元一样容易”，这样的观点也并不是完全没有道理。

    如果苹果以每股600美元的价格回购股票，后来股价跌至每股400美元，留下来的股东就亏了——公司多付了30%的价钱。同样，如果股价继续以现有速度上涨（自去年12月以来涨了30%）达到近700美元或800美元，苹果在什么样的价位上回购股票才能真正具有经济上的意义？

    为了让当前600美元的股价合理，米兰诺计算得出，苹果若要延续其经济赢利能力，需要将2016财年的销售额增至3,000亿美元。苹果最近一个财政年度的销售额为1,080 亿美元。

    How high does Apple's stock need to rise to make its promised buyback worthwhile? It's a question worth asking. After all, Apple could have spent the $10 billion it announced in share buybacks on any number of things to grow shareholder value—a bigger dividend than the annual $9.9-billion payout announced, which currently yields 1.8%, or even a one-time special-dividend.

    To answer the question, Gregory Milano of Fortuna Advisors, which advises Fortune 500 companies on maximizing their market value, did some quick math. Milano considers buybacks to be like any other investment a company can make. Buybacks must offer a good return in order to be deemed a smart use of capital. That is, if a company buys its stock at $10 a share and it rises to $12 next year, it's earned a 20% "return on investment" for shareholders. Because the average business's capital costs run 10% a year, between debt and equity expenses, most companies should seek buybacks to return more than 10% a year if they want to build shareholder profit.

    In Apple's case, returns on capital are extraordinary. The tech giant earns around a 40% return on its operating capital, far exceeding its capital costs. So what's a good hurdle rate, or minimum rate of return, for its buyback? Milano thinks a 20% "return on investment" is fair.

    For the buybacks to deliver that return, Milano says Apple's stock price will have to rise 128% to $1,368 over the next five years. For a meager 10% buyback return, the stock needs to hit $984 in five years.

    Can the stock reach those heights? Everything is working in Apple's favor today. Shares have risen 82% over the past year. In the first quarter alone it recorded $16 billion in free cash flow on screaming hot sales of iPads and iPhones. But nothing is certain in the stock market. It's not unfair to think the stock could jump to $800 as easily as it could fall back to $500.

    If Apple buys shares at $600, and the stock later drops to $400, its remaining shareholders are penalized—the company overpaid by 30%. Likewise, if shares keeps rising at their current pace —up 30% since December—to reach levels near $700 or $800, at what point does Apple (AAPL) ask if it truly makes economic sense to buy shares at such a high level?

    To justify its current $600 stock price, Milano has calculated that Apple, continuing its level of economic profitability, needs to grow sales to $300 billion in fiscal 2016. It recorded sales of $108 in the latest fiscal year.