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 homebuilders including KB Home (NYSE: KBH), PulteGroup (NYSE: PHM), Lennar (NYSE: LEN), Toll Brothers (NYSE: TOL), D.R. Horton (NYSE: DHI), and Beazer Homes (NYSE: BZH) were up big today, as they all notched gains of 10% or more during intraday trading after a positive report from the National Association of Home Builders.

So what: The NAHB report showed that the homebuilder sentiment index rose to 18, above both the reading of 14 last month and the 15 that was expected. The level still suggests a very dour outlook -- anything below 50 means there is more pessimism than optimism -- but the direction of the move is a definite positive for an industry that has been absolutely ravaged since the housing market imploded.

Now what: As the yet-lackluster sentiment gauge suggests, there is still plenty of clawing back ahead for the beleaguered industry. While today's news may be a good step, there are plenty of other numbers that investors need to watch, including sales figures, inventories, and prices. The quick pop from an unexpectedly good NAHB report is the stuff that gets traders fired up, but for longer-term investors this isn't enough reason to jump in on today's action.

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