????近幾個季度，美國企業界利潤大幅攀升，但這種好日子可能來日無多了。周二美股盤后，制造業巨頭美國鋁業（Alcoa）將率先拉開一季報序幕。分析師們預計標準普爾500指數的總利潤將顯著放緩，可能預示著市場拐點的到來。去年，標準普爾500指數的每股收益增幅介于8.4%-19.7%之間不等，但今年多重因素可能壓制利潤。

????為了解哪里利潤可能下跌，敬請關注四大指標：

蘋果指標

????蘋果公司（Apple）或許只是標準普爾500指數的一家成分股公司，但近年來，它對該指數的影響已遠超一家公司應有的影響。截至去年年底，標準普爾500指數的總利潤較上年增長約6%。如果剔除蘋果公司利潤增長116%因素，總利潤增幅將僅為3%。

????預計一季度標準普爾500指數的總利潤將同比下降0.1%。如果沒有蘋果公司亮麗的季報，結果會更糟。金融數據和軟件公司FactSet上周發布的一份報告預計，如果剔除蘋果，標準普爾500指數的總利潤跌幅將更深，達到1.6%。鑒于蘋果公司的盈利能力在科技業影響力日益重大，標準普爾500指數科技公司利潤預計將增長3.4%。如果剔除蘋果，凈利潤實際上將下跌4.7%。蘋果公司定于4月24日盤后發布季報。

新興市場

????即便是在美國經濟復蘇乏力之時，美國一些最大的公司利潤卻逆勢飆升。這主要是因為企業管理者削減了成本，裁減了人員，同時也因為他們將銷售轉向了印度、中國和巴西等地。

????自從2009年全球經濟衰退以來，發展中國家成了全球經濟增長的主力，而歐洲、美國則仍在苦苦掙扎，努力從金融危機中謀求復蘇。但新興市場增長正在放緩的跡象可能會損害美國公司的盈利能力。

????以美國最大的電解鋁生產商——美國鋁業（Alcoa）為例。華爾街預計由于中國、歐洲等關鍵市場的增長放緩，美國鋁業將公布虧損。事實上，分析師們和策略師們將關注這家公司如何應對電解鋁庫存過剩以及價格下跌問題，但正如商業網站Business Insider指出，他們同樣也關注著中國這個全球最大的電解鋁消費國的經濟前景。

燃料價格

????銷售可能強勁，但從運輸材料到維持工廠機器運轉所需的燃料價格上漲預計將拖累很多大公司的利潤。

????今年年初，布倫特原油的平均每周價格為118.86美元，顯著高于上年同期的平均106.27美元。

????FactSet的高級盈利分析師約翰?巴特斯預計，標準普爾500指數中有104家公司的一季度銷售額將實現良性增長，但凈利潤會出現下降。剔除銀行和其他金融公司，凈利潤率預計將為8.4%，是2010年第一季度以來最低水平。

????Corporate America has seen profits soar for the past several quarters, but the party may not last much longer. After markets close on Tuesday, manufacturing giant Alcoa will kick off a slew of earnings results for the first quarter. Analysts expect overall earnings in the S&P 500 to significantly slow, possibly signaling the beginning of a turning point in the market. Last year, earnings per share in the S&P 500 grew in the range of 8.4% to 19.7%, but several factors could crimp profits this year.

????To get a sense of where earnings might fall, watch for these four key indicators.

The Apple indicator

????Apple (AAPL) might only be one company in the S&P 500, but lately it's had far more influence on the index than any one company should. At the end of last year, overall earnings for S&P 500 rose about 6% compared to the previous year. If Apple's 116% profit surge was excluded, earnings would have risen only 3%.

????For the first quarter, overall earnings are expected to decline 0.1% compared with a year earlier. But it could be worse without another stellar quarter from Apple. According to a report by FactSet released last week, the S&P 500 could see a deeper 1.6% fall if Apple were excluded. Given that the company's profitability weighs heavier in the technology sector, earnings among the S&P 500 tech companies are forecast to grow 3.4%. Without Apple, earnings would actually fall by 4.7%. The tech company is scheduled to release its earnings after markets close on April 24.

Emerging markets

????Even as the U.S. struggles with a tepid recovery, America's biggest companies have seen profits soar. Not only is it largely because executives trimmed costs and laid off workers, but it's also because they've turned to places like India, China and Brazil for sales.

????Since the global recession of 2009, the developing world has largely driven growth across the globe while Europe and the U.S. struggle to recover from the financial crisis. But signs that growth in emerging markets is slowing will likely hurt profits at U.S. companies.

????Take Alcoa (AA) for instance. Wall Street expects the largest U.S. producer of aluminum to post a loss as the pace of growth slows in key markets like China and Europe. Indeed, analysts and strategists will be looking at how the company is coping with a glut of inventory and weaker prices, but, as Business Insider has pointed out, they'll also focus on the economic outlook of China – the world's biggest consumer of aluminum.

Fuel costs

????Sales may be robust, but paying higher fuel costs to do everything from transporting materials to running machines at factories is expected to erode profits at many big companies.

????The average weekly price for Brent oil was $118.86 at the beginning of this year – markedly higher than the average $106.27 recorded around the same period last year.

????FactSet senior earnings analyst John Butters expects that 104 companies in the S&P will see healthy growth in sales during the first quarter, but also a decline in earnings. Excluding banks and other financial companies, net profit margins is expected to come in at 8.4%, the lowest since the first quarter of 2010.????