Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (DJINDICES:^DJI) has enjoyed solid gains so far today, with the stock market benchmark up 44 points as of 12:25 EDT after giving up this morning's triple-digit gains. But tomorrow, Boeing (NYSE:BA), Caterpillar (NYSE:CAT), and AT&T (NYSE:T) continue the line of Dow component companies reporting earnings this week. With the government struggling to catch up with economic reports that were delayed during the shutdown, earnings could be the primary factor in moving the Dow tomorrow.

Boeing and Caterpillar are scheduled to release their reports before the bell, with Boeing following up with a conference call at 10:30 a.m. EDT and Caterpillar holding its call at 11 a.m. EDT. AT&T reports after the market closes, with a start time of 4:30 p.m. EDT for its conference call.

Boeing arguably has the most at stake in its earnings report, as its stock has soared to new all-time record highs. Expectations are high because of huge demand from airlines eager to update their fleets to take advantage of the more fuel-efficient aircraft that Boeing has produced lately. But ongoing issues with the 787 Dreamliner threaten to distract attention from Boeing's other successes. Still, the trend toward modernization could last for years, making it important to put any single quarter's results into a longer-range context before making knee-jerk investing decisions.

For Caterpillar, investor expectations are at the other extreme. Pessimism continues to grip the stock as Caterpillar struggles from tough conditions in both the construction-equipment and mining-equipment business segments. The heavy-equipment giant has warned of potential long-term weakness in earnings for quite a while, and so far, conditions in key markets like China haven't improved nearly enough to warrant a sharp reversal of negative sentiment. Yet with such low expectations, even the hint of positive news might be enough to send Caterpillar stock higher.

AT&T, meanwhile, has questions to answer about its future strategic plan for growth. The recent sale of its wireless-tower assets should raise cash for network improvements and moves to enhance shareholder value. But the bigger issue facing the telecom giant is how it can handle increasing levels of competition while still leaving itself room for growth, either domestically or abroad. Results in light of the recent launch of the newest iPhone offerings will be important, but in the long run, it'll be much more important for AT&T shareholders to see signs of smart corporate decision-making as it applies to AT&T's strategic vision.

Fool contributor Dan Caplinger has no position in any stocks mentioned. You can follow him on Twitter @DanCaplinger. The Motley Fool has no position in any of the stocks mentioned. 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.