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: Shares of building materials manufacturer USG (NYSE: USG) are 10% higher this afternoon following an unexpectedly positive earnings announcement from homebuilder Lennar (NYSE: LEN).

So what: Make no mistake about it -- USG is simply riding Lennar's coattails higher today after the homebuilder reported a 20% jump in orders and a 9% rise in deliveries. Perhaps even more surprising, selling prices for homes rose slightly during the quarter. Lennar also forecast that the strength it was seeing in new orders is expected to continue in 2012.

Now what: This is just the type of news that could invigorate an ailing housing sector and USG, a company that supplies an array of products used in new construction and in remodels. If things are going well for homebuilders like Lennar, that's likely to trickle down to USG, so today's move makes sense. I'm nowhere near brave enough to call one earnings report the end-all to the housing sector's woes, but I see building materials suppliers as a better and less-volatile bet going forward. USG definitely looks like one worth watching.

Craving more input? Start by adding USG to your free and personalized watchlist so you can keep track of the latest news with the company.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.