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.

What: Western Digital Corporation (NYSE: WDC) popped 19% in intraday trading today after the company announced a deal to acquire Hitachi's hard-disk drive business for about $4.3 billion.

So what: The companies' strengths complement each other nicely, with WDC strong in the consumer segment and in North America and Europe and with Hitachi strong with corporations and in Asia. This also removes a competitor that had occasionally pressured industry profits with aggressive pricing.

Now what: Hard-disk drives are under pressure, particularly in the consumer segment, from solid-state drives and from a demand shift to devices that don't use hard drives, like tablets and smartphones. Aside from acquisition-related charges, WDC expects the deal to boost EPS. While acquisitions typically fall short of expectations, this deal should benefit from sound logic and WDC's solid execution.

Interested in more info on Western Digital? Add it to your watchlist here.

Fool contributor Cindy Johnson does not own shares of any company named above. 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.