Earnings season is in full swing, and a full third of companies on the Dow Jones Industrial Average (DJINDICES:^DJI) is set to report last quarter's data this week. From industrial giants such as Caterpillar (NYSE:CAT) to Big Oil icons like ExxonMobil (NYSE:XOM) and Chevron (NYSE:CVX), seemingly every sector of the blue-chip index is on pace to capture investors' attention in the next few days. Let's take a look at what you should be watching out for as 10 of America's most prominent stocks face their biggest test so far of 2013.

Five days of earnings
Caterpillar's set to start a busy week for blue-chip investors when it reports earnings data on Monday. The industrial stock's been hammered in 2013, losing nearly 14% year to date as China's economic slowdown has hampered the company's growth. Analysts are expecting a big hit to the company's financials, projecting a 39% dip in earnings per share over a year ago, with a year-over-year drop in revenue of more than 13%. The company's sales have dropped in recent months, and it could be a while before this stock makes a recovery. Don't expect a miracle from this earnings season.

Things heat up on Tuesday for Dow investors, with four companies on the index reporting quarterly data. Analysts expect $0.01 year-over-year earnings gains from Travelers (NYSE: TRV) and DuPont (NYSE: DD), projecting average EPS figures of $2.02 and $1.52, respectively, while estimating United Technologies' (NYSE: UTX) earnings to dip $0.01 from last year's quarter to $1.30. AT&T (NYSE: T) is also expected to succeed in its earnings on Tuesday, with experts projecting earnings of $0.64 per share, a year-over-year gain of more than 6%. AT&T's stock has shot up by nearly 14% in the past three months alone, and an earnings beat could send shares even higher.

Analysts predict a 2% year-over-year rise in earnings to $0.96 at Procter & Gamble (NYSE: PG) when the conglomerate reports data on Wednesday. Aerospace giant Boeing (NYSE:BA) is also set to report that day -- with analysts estimating an EPS jump of 21% to $1.48, despite projecting a 2.8% sales decline -- and while the company's trouble over the grounding of its 787 Dreamliner jet has dominated headlines this year, don't expect the drama to affect its quarterly data. Boeing hasn't lost any of its previous orders for the grounded plane, which got a boost on Friday, after the FAA approved the company's battery fix for the jet. Still, investors should keep an eye out for anything company management reveals about estimated financial fallout from the 787's trouble.

Both companies reporting on Thursday, 3M (NYSE: MMM) and ExxonMobil, are expected to post year-over-year EPS growth. Analysts expect the former to nose higher by around 4% in both earnings and revenue, with an average EPS estimate of $1.65. Exxon's expected to see sales fall more than 3% year over year, but analysts still project an average EPS figure of $2.05, a slight increase over last year's $2 figure for the same quarter. Exxon recently nosed past Apple (NASDAQ: AAPL) to retake the title of the world's most valuable publicly traded company, even as shares have fallen more than 3% year to date.

Analysts aren't so optimistic about earnings at Exxon's fellow Big Oil competitor Chevron, which rounds out the Dow's week by reporting data on Friday. Although Chevron's expected to post double-digit sales growth and revenue of more than $67.7 billion, the company's projected to see earnings per share decline slightly to $3.07 for the quarter. Chevron's stock has performed better than Exxon's in 2013, with shares gaining around 5%; still, the stock has underperformed the majority of the Dow so far.

Fool contributor Dan Carroll has no position in any stocks mentioned. The Motley Fool recommends 3M, Apple, Chevron, and Procter & Gamble and owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.