The big macro can cause big moves in the market. What does today's headline macro news mean for your portfolio?

What's happening: The National Association of Realtors released its monthly data on existing-home sales, which showed sales at an annual rate of 4.91 million. That number was down from 5.06 million in August, but roughly in line with expectations. Home prices continued to fall, with the national median existing-home sales price falling 3.5% from September of last year.

In plain English, please: Earlier this week we watched the stocks of homebuilders surge as the National Association of Home Builders reported an increase in homebuilder sentiment. The existing-home sales report today could provide some offset to that burst of optimism. As existing-home sales constitute a much larger portion of the home sales market than new homes, homebuilders face serious competition from that part of the market.

Looking to the broader economy, while the report isn't necessarily bad news, a stronger pickup in housing-market activity would be a definite positive for the economy.

Stocks to watch: While activity in the housing sector impacts many different types of companies, homebuilders are the most closely tied to it. This news is particularly meaningful for the same stocks that were jumping earlier this week -- KB Home (NYSE: KBH), PulteGroup (NYSE: PHM), Lennar (NYSE: LEN), Toll Brothers (NYSE: TOL), D.R. Horton (NYSE: DHI), and Beazer Homes (NYSE: BZH).

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