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.

In a shining example of the market's irrationality, the Dow Jones Industrial Average (DJINDICES:^DJI) has taken a sharp turn lower today. As of 2:25 p.m. EDT, the blue-chip index has plunged 91 points after recovering from this morning's even steeper losses. What's driving today's drop? Nothing more than the usual speculation and Wall Street worries about the tapering of the Federal Reserve's quantitative bond-buying later in the year -- something that's bound to happen eventually.

Let's look past stimulus-watch at the big stories on today's Dow.

Disney's earnings take center stage
Disney
's (NYSE:DIS) making waves today before its earnings release, with the stock up about 1.6% to lead the Dow's small contingent of risers. Analysts aren't expecting a boom from the company's report today, projecting just 1% year-over-year growth in EPS and 5% growth in revenue. Disney's film segment has done well this year with several high-profile hits, but many analyst eyes are on the box-office bomb The Lone Ranger and its impact on the company's performance. The film couldn't live up to the hype brought about by a stellar cast and massive budget, and at least one analyst projects  a writedown of about $150 million.

Even with that loss, Disney's breadth and diversity bode well for the future -- and for today's earnings. Advertising boosts from networks like sports channel ESPN and ABC well help mitigate any damages to the company's studio division, and investors must also watch how Disney's parks managed during the critical summer season.

IBM's (NYSE:IBM) certainly not having that good of a day, with shares down more than 2.5% to lead the Dow downward. The company announced an alliance with Google, Nvidia, and other firms to license its chips in order to grow the segment. IBM's taking a shot at rival Intel (NASDAQ:INTC), which has pivoted toward the server arena in order to offset declining revenue from the lagging PC market.

IBM's Power chip technology will power cooperatively built server and network centers under the deal, and the company will need all the help it can get. The firm's power systems division saw revenue fall about 25% in the last quarter, and Intel has managed to maintain a dominant position in the industry so far.

The news hasn't hit Intel as badly today: The chipmaker's shares are down 0.8%. Until IBM can manage a real push against the dominance of Intel and rival ARM, Intel will be in good shape -- even as it manages its declining PC unit, a market it dominated for years. The company has begun pushing into the mobile segment, and Intel must prove to investors that it can successfully extend its solid position among chip makers into this and other growing markets.

Fool contributor Dan Carroll has no position in any stocks mentioned. The Motley Fool recommends Google, Intel, and Walt Disney. The Motley Fool owns shares of Google, Intel, International Business Machines, and Walt Disney. 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.