The US stock market is set to hit a new milestone on Thursday, surpassing the postwar boom as the second-longest sustained period of rising share prices, even as questions intensify about the health of corporate profits.

虽然有越来越多的人质疑美国企业利润的健康状况，但美国股市本周四仍有望创下一个新的里程碑，超越战后的繁荣期、录得美国史上持续时间第二长的牛市。

It comes in a week when statements from central banks in the US and Japan will be heavily scrutinised for the extent of official support for asset prices, highlighting the parallel boom in safe securities such as government debt.

本周，市场还将仔细研读美国及日本央行的声明、以把握政府对资产价格的支撑力度。这件事让人们注意到，国债等避险证券同样处于牛市中。

The longest sustained US rally apart from the bull market of 1987 to 2000 highlights a conundrum: stock market valuations imply a future of rosy profits and economic optimism at the same time as sovereign bonds are priced for a stagnant world of diminished opportunity and minimal inflation.

美国股市这轮涨势的持续时间之长将仅次于1987年至2000年的牛市。这轮涨势凸显出了一个难以解答的问题：股市的估值暗示未来利润乐观、经济形势喜人，而主权债券的定价却暗示未来机会减少、通胀极低、增长停滞。

Laurence Mutkin, global head of G10 rates strategy at BNP Paribas, said the twin rallies were the result of the paradox of official programmes of bond buying, or quantitative easing.

法国巴黎银行(BNP Paribas)十国集团利率策略全球主管劳伦斯•穆特金(Laurence Mutkin)表示，股债双牛是由官方债券购买计划（即量化宽松计划）的悖论造成的。

“The bond market is not just the barometer of market expectations it is also a policy tool for central banks,” he said. “That means prices don’t just reflect investor views of the underlying economy.”

他说：“债券市场不仅是市场预期的晴雨表，也是央行的政策工具。这意味着，债券价格不仅仅反映投资者对经济基本面的看法。”

Analysts forecast the earnings of S&P 500 companies to fall 7 per cent in the first quarter of 2016, compared to the same period the year before, according to Thomson Reuters.

汤森路透(Thomson Reuters)的数据显示，分析师预计标准普尔500指数(S&P 500)成份股企业2016年首季度利润同比下降7%。

From the March 2009 low point US stocks will have risen for 2,607 days on Thursday, according to Bank of America Merrill Lynch, surpassing the long expansion of June 1949 to August 1956.

美银美林(Bank of America Merrill Lynch)的数据显示，到本周四，美国股市始于2009年3月低点的这轮牛市的持续天数将达到2607天，超过1949年6月至1956年8月的那轮“长牛”。