黄金为何光芒不再

    债券收益率一向与价格反向而动，但它目前已跌至历史低位。10年期美国国债收益率降至1.87%——表明投资者对于此类证券的胃口并没有降低多少，即便标准普尔曾经警告称，美国已经不再是最安全的借款人。

投资者没有过多担忧通货膨胀

    北卡罗来纳州大学（University of North Carolina）威明顿分校的金融教授瑟汀•辛内说，投资者蜂涌而至投资债券也表明，他们并不十分担忧通货膨胀。这也部分解释了金价的下跌；黄金常常被用作应对物价持续上涨的保值工具。

    对黄金市场有广泛研究的辛内表示：“很难预测金价最终会走向哪里，但归根结底，基本面已经不存在了。黄金不再是人们曾经认为的安全投资了。现在投资黄金实际上已经变得十分危险。”

金价已跌至200日移动均线之下

    金价跌破200日移动均线时，投资者通常都会引起警觉。上周，金价两年来首次跌破200日均线1,615美元/盎司，目前报于1,613美元/盎司。尽管分析师们并未据此宣告进入熊市，但波士顿大学（Boston University）的金融学讲师马克•威廉姆斯表示，投资者应当将此视为“警示信号”。

    “下一阻力位是1,500美元，”曾任场内交易执行的威廉姆斯表示。“如果金价跌破这一水平，将进一步证明，9月份在1,900美元上方见顶的黄金泡沫已开始破裂。”

黄金价格超过铂金

    再来看铂金，这是一种同时还具备工业用途的贵金属。从历史上看，铂金价格通常比黄金价格高100美元或更多。但8月份当金价接近近期峰值，这种状况发生了变化。威廉姆斯指出，这是表明金价虚高的另一个指征。他说，以当前铂金价格1,400美元/盎司来看，黄金价格可能跌至1,300美元甚至更低。

    Bond yields, which move opposite of prices, have fallen to historic lows. Ten-year Treasuries have dropped to 1.87% -- proving that investors' appetite for such securities haven't waned much, even as S&P warns that the U.S. is no longer the safest of borrowers.

Investors aren't too worried about inflation

    The flock to bonds also signals that investors aren't very worried about inflation, says Cetin Ciner, finance professor at the University of North Carolina in Wilmington. This partly explains the fall in gold, which is often used as a hedge against steadily rising prices.

    "It's very hard to predict where prices could go, but ultimately the fundamentals are not there," says Ciner, who has done extensive research on the gold market. "It's not the safe investment that people thought it was. It has actually become very dangerous right now."

Prices have fallen below gold's 200-day moving average

    When gold falls below the 200-day moving average, investors typically take notice. Last week, for the first time in two years, the precious metal fell below the average of $1,615 an ounce and is currently trading at $1,613 an ounce. Though this hasn't led analysts to call a bear market, Boston University finance lecturer Mark Williams says investors should take the development as a "wake-up call."

    "The next resistance level is $1,500," says Williams, a former trading floor executive. "If gold drops below this floor, it is further proof that the bubble, which peaked in September at more than $1,900, has begun to burst."

Gold beats platinum

    And then there's platinum, a precious metal that also has industrial uses. Historically, platinum trades at a premium of $100 or more over gold. But that shifted in August when gold neared its most recent peak. Williams points out that this is another indicator that gold prices are inflated. At current platinum prices of $1,400 an ounce, gold could fall to $1,300 or lower, he says.