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 Industrials (DJINDICES:^DJI) got off to a quiet start to the holiday week, rising 31 points as of 10:57 a.m. EST to stay solidly above the 16,000 mark. The apparent resolution of the Iranian nuclear standoff through negotiations over the weekend made investors somewhat cheerful going into Thanksgiving, but concerns about the holiday shopping season will likely linger throughout the week. Among the big movers within the Dow, Boeing (NYSE:BA) led declining stocks, Caterpillar (NYSE:CAT) was the biggest gainer, and Wal-Mart (NYSE:WMT) posted a modest advance after making a big announcement.

Boeing fell 2.5% after announcing yet another setback for its 787 Dreamliner aircraft. Over the weekend, Boeing said that Dreamliners that have engines from General Electric (NYSE:GE) face the risk of ice-crystal formation when flying near areas of thunderstorm activity. Those crystals can reduce the amount of thrust the engines generate. Boeing also noted the issue on its 747-8 aircraft models. Boeing has recovered from similar issues before, but it doesn't need any more negative publicity for the Dreamliner than it has already received. General Electric shares only fell 0.6%, suggesting that investors don't see the issue as a big problem for the aerospace-engine maker.

Caterpillar rose 2.3% after getting a favorable upgrade from analysts at Bank of America. Despite the heavy-equipment maker's terrible sales lately, BofA said good things about the company's power-systems segment, which has become an increasingly important part of Caterpillar's overall operations. Because construction activity could stay muted for the foreseeable future, and mining-equipment sales will likely remain under pressure as long as commodity prices are falling, Caterpillar's ability to use its diversified offerings to produce growth will be important in helping the stock rebound from big losses recently.

Wal-Mart gained about 0.7% as the retailer announced a leadership. CEO Mike Duke will retire in early 2014, with Wal-Mart tapping Doug McMillon to take over as the company's new top executive. McMillon is CEO of Wal-Mart's international division, and has served in various roles including heading the Sam's Club division during the turbulent years from 2006 to 2009. A company spokesman said Duke's decision was personal, but given the challenges the retailer faces going into the holiday season, the timing certainly could have a role in how shareholders perceive Wal-Mart's holiday results.