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After a morning session that saw the Dow Jones Industrial Average (DJINDICES:^DJI) lose more than 100 points, stocks across the markets have rebounded nicely this afternoon. As of 2:25 p.m. EDT, the Dow is up 57 points, with most of the blue-chip index's stocks in the green. The index hasn't been held back by a weak jobs report showing a U.S. labor market in flux. Let's catch up on the stock action you need to know about.

Gloom settles over the labor market
The labor force isn't seeing much of an uptick -- at least, certainly not in August. While August's unemployment rate declined from 7.4% to 7.3%, the U.S. economy added just 169,000 jobs for the month, falling slightly below economist predictions. Worse, America's labor participation rate declined to 63.2%, a multidecade low that has come about as more and more out-of-work Americans give up on job-hunting.

However, the labor market pessimism hasn't hurt stocks too badly despite this morning's drastic fall. Caterpillar (NYSE:CAT) ranks among the Dow's leaders today, with shares gaining 1.2%. It's been a rough road for Caterpillar in 2013, with the stock gaining just 1.8% year to date. Morgan Stanley didn't help yesterday when it cast a cautious outlook for the company's future, saying Catepillar's visions of growing construction-equipment demand could go unrealized if the mining sector can't rebound from its serious slump.

Yet that business hasn't even been Caterpillar's worst segment in 2013. Construction equipment does account for the second-largest part of the company's sales, and the segment's revenue fell 13% year over year in the first half of 2013, with Asia-Pacific sales seeing a particularly steep decline. However, Caterpillar's resource-industries unit isn't far behind in terms of overall revenue through the year's first half, and in that time span, resource-industries sales plummeted 29%, including a 44% fall in the Asia-Pacific region. Caterpillar will need more than just one of its core businesses to kick-start revenue growth if it wants to turn its fortunes around.

UnitedHealth (NYSE:UNH) is also having a nice day so far, with shares up 0.7%. Unlike Caterpillar, this stock has had a wonderful run in 2013: UnitedHealth's shares are up more than 37% year to date. What has helped drive this run? Besides the company's size -- UnitedHealth is America's largest publicly traded private insurer by membership -- the company has also managed to keep premium growth surging higher. Premium revenue grew by 11% over the first year of 2013.

In the insurance industry, however, all eyes are watching the arrival of health care reform in 2014. While the Kaiser Family Foundation recently released   a study showing that Obamacare premiums might not rise as much as anticipated through reform, UnitedHealth has taken a cautious approach to state-run insurance exchanges. Considering the influx of perhaps millions of previously uninsured Americans into the insurance exchanges next year and the potential costs that could follow, UnitedHealth's approach looks like a good move for investors for now.

Fool contributor Dan Carroll has no position in any stocks mentioned. The Motley Fool recommends UnitedHealth Group. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.