After many failed turnaround attempts, it appears the housing sector may finally have a foundation under it once again. Existing-home sales ticked higher by 2.8% in August to an annual rate of 4.82 million units -- the fastest rate reported since May 2010. This news also came on the heels of a 5.5% increase in single-family home construction. Driven by the prospect of stabilizing home prices, the S&P 500 (INDEX: ^GSPC) rose by 1.73 points (0.12%) to 1461.05. Let's have a look at a few notable movers within the S&P 500 today.

Companies that helped the S&P 500
As should be no surprise, the sector leading today's rally higher is homebuilders, led by the largest builder in the U.S., D.R. Horton (NYSE: DHI), up better than 4%. D.R. Horton reported a 25% increase in new-home orders in its most recent quarter and has been commanding better pricing power, which has helped its homebuilding margin. My Foolish colleague Andrew Tonner has been notably optimistic about a housing recovery and recently outlined his reasons that this rebound could be the beginning of a long-term uptrend in housing.

Regions Financial (NYSE: RF), whose loan portfolio was hit particularly hard during the housing downturn, is a side beneficiary of today's housing data. In addition to Regions' repayment of its TARP loans and a drastic improvement in its credit quality, today's data suggest that the housing market is stabilizing, which could be construed as a positive for homeowners currently underwater and struggling with their payments, as well as for Regions' commercial mortgage portfolio. Regions tacked on 5% today.

Companies that hindered the S&P 500
Chip-equipment manufacturers had a particularly rough day, with KLA-Tencor, Applied Materials, and Lam Research (Nasdaq: LRCX) all heading decisively lower following negative comments from Citigroup. Blaming Apple for a fabless semiconductor production shift to Taiwan Semiconductor from Samsung, Citigroup analyst Terence Whalen cut estimates across the sector and dropped Lam Research to a "hold" from a "buy." Consider me unconcerned about today's ratings change, however, as I opined earlier in the week why Lam Research could be an excellent pickup near its 52-week low.

Waste Management (NYSE: WM) also found itself being trashed by JPMorgan Chase, which lowered its rating on the waste-management and recycling company to "underperform" from "neutral" while dropping its price target to $34. JPMorgan cited volatile commodity prices as the impetus for the downgrade that sent the stock down nearly 4%. I, for one, am siding with Fool Alyce Lomax and see considerably more upside than downside for Waste Management.

Chipping away?
Will Apple's shift away from Samsung and to Taiwan Semiconductor affect production and profitability? Find out the answer to this question and much more by getting your copy of our latest premium research report on Apple. Crammed with in-depth and unbiased analysis on the opportunities and threats facing Apple, and complete with a full year of regular updates, this report will give you the investing edge you need to be a successful long-term investor in Apple.