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: Titanium dioxide manufacturer Kronos Worldwide (NYSE: KRO) quadrupled its profit in the second quarter, but that isn't saving the stock from a 13% sell-off today.

So what: Sales of $538 million and profits of $0.77 per share beat analysts' Q2 estimates with a stick. What's more, management says it's already maxing out capacity at its production facilities, and believes a "significant global shortage of TiO2 products will continue for several years," ensuring strong profit margins at Kronos and helping "cash flows and profitability to continue to increase beyond 2011."

Now what: Honestly, I'm not sure what's not to like in Kronos' report -- or Kronos' stock. At 19 times earnings, it doesn't seem unreasonably priced relative to Street projections of 21% long-term annual earnings growth. Management seems to be confirming that the growth is real, and sustainable. Heck, Kronos even pays its shareholders a modest 1.9% dividend.

Seems to me, any investors selling the stock today are being penny-wise (to capture the stock's 100% gain over the past year), but pound-foolish (small "f"). There's no reason to think Kronos' time has run out.

Want to explore Kronos further? Add it to your Fool Watchlist.