One question on the minds of innumerable investors, analysts and journalists during the United States earnings season now in the books is: "What's going on in China?"

Before the $ood of fourthquarter earnings reports began, the word on Wall Street was "everybody's going to be looking at China," said Kenneth Polcari, director of New York Stock Exchange floor operations at O'Neil Securities.

Polcari explained that China "has the second-largest economy in the world. So everyone wants to see it do well". To put it simply, China "can help the US economy to do better".

While China's profit-making value to the US climbs each day the US remains mired in its economic rut, this latest, intense display of interest in China underscores the extent to which the US business community has come to depend on China to help drive profits.

Alcoa kicked off the fourth-quarter earnings season by reporting results that hit its earnings target and gave an upbeat full-year outlook for global aluminum demand. But what helped drive up shares of the largest US aluminum producer was CEO Klaus Kleinfeld's statement on CNBC. He said that "what we're seeing in the world market and our end markets is China is clearly coming back".

China also grabbed headlines by bringing good news to Apple, the iconic maker of the iPhone and the iPad. Thought it posted disappointing earnings, it released its sales results from Greater China for the first time. The company said sales from China (including Hong Kong and Taiwan) surged 67 percent from the previous year. Apple's China sales were higher than the company's sales in Japan and higher than the rest of Asia. In a conference call, Apple CEO Tim Cook told analysts the company would continue to expand its retail channels in China as it competes with Samsung and other phone makers.

The fourth-quarter results also underscored China's ability to carry the ball for US corporations navigating an uncertain and stormy financial landscape.

General Motors Co eked out a third money-making year after an epic US government bailout and restructuring partly from the revenue earned in China. Although GM posted a weaker-than expected profit for the latest quarter - due to wider losses in Europe and rising costs in North America - adjusted earnings before interest and taxes for international operations, mainly in China, jumped 25 percent. Re$ecting the country's growing importance to GM, for all of 2012, GM outsold Volkswagen in China, while deliveries at GM and its Chinese joint ventures rose 11 percent. GM and its partners in China captured 14.3 percent of the market in the latest quarter.

As David Zoia, editorial director of Wards Auto, an industry information website, put it: "China's been very critical for GM. During the 2009 downturn and bankruptcy, when things were at their worst in North America, China was carrying the ball for GM. The potential that is still there makes it even more critical to them. It's a huge market, and one nobody can ignore. All companies have their eyes on it".

China's in$uence, however, translated into bad news for fast-food restaurant chain owner Yum Brands. Yum, which operates more than 4,000 KFC restaurants in China and is considered a model for how a foreign company can succeed in China, saw its earnings and outlook take a hit after customers shunned its restaurants over a tainted chicken scandal. With sales at stores open at least a year in China dropping 6 percent in the quarter, compared with a 3 percent increase in US same-store sales, the company has announced qualitycontrol measures in China aimed at restoring confidence in the brand. Ma Wenfeng, a food industry analyst , said the chicken scandal hit Yum harder than expected.

"As Yum's most important global market, the company will feel the eJect of sluggish sales revenue in China for a while," Ma said.

As the fourth-quarter earnings season ends, developments not only in China, but also in Japan and Europe, such as the debate over a financial bailout for Cyprus and the aftermath of Italy's inconclusive election, will contribute to what is expected to be a volatile quarter.

But amid all that, lurking in the background will be the question that US corporate executives, investors, analysts and journalists seem to want answered with increasing regularity:

"What's going on in China?"

Contact the writer at michaelbarris@chinadailyusa.com