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

Expect a flat start to the stock market today, as the Dow Jones Industrial Average (DJINDICES:^DJI) is set to rise a meager 14 points at the opening bell. News is breaking this morning regarding Scripps Networks Interactive (NASDAQ:SNI) and Costco (NASDAQ:COST), while Home Depot (NYSE:HD) gave investors an updated long-term earnings forecast.

But first, Scripps Networks is on the move this morning on reports that Discovery Communications (NASDAQ:DISCA) may be looking to purchase the company. Scripps owns several popular TV content brands, including Food Network and HGTV, while Discovery owns TLC, Animal Planet, and the Discovery Channel, among others. Merging the two portfolios could make more sense now, given that consolidation is coming to the cable industry, and could soon give cable operators more power to push back against content producers' prices. Scripps Networks' stock is up 6.6% in premarket trading.

Costco this morning reported soft results for its fiscal fourth quarter. Profit came in at $0.96 a share, below the $1.02 that Wall Street was targeting -- and just a penny higher than last year's haul. Revenue was also about $1 billion below estimates, registering an increase of just 5% to $24.47 billion. But that seemingly disappointing result could be partly due to a quirk of the calendar. Costco's fourth quarter this year ended on Nov. 24, before the Black Friday shopping weekend, while last year's Q4 included most of that weekend. In any case, membership fees continued to trend higher this past quarter, and comparable-store sales increased by 4% in the U.S., which is likely better than most retailers could manage. Costco's stock is down 1.7% in premarket trading.

Finally, Home Depot expects a fundamental improvement in its business to continue for years. The retailer this morning affirmed its outlook for the rest of 2013, saying that comparable-store sales growth should come in at 7%. It also provided an earnings forecast for 2014 that includes a 17% boost in per share profit. Home Depot updated its 2015 financial targets as well, and now sees operating margin rising to 13%, while its return on invested capital should climb to a stellar 27%. With solid sales results and a strong outlook like that, one has to wonder how the stock has managed to trail the broader market this year. After you're done wondering, consider adding this impressive retailer to your portfolio. Home Depot's stock is unchanged in premarket trading.