Stocks close mixed, but post best July since 2010; FB ends below $38

Stocks wrapped up the final trading day of the month on a flat note, but still logged their best July since 2010, as the Federal Reserve said it will maintain its bond-buying policy in its ongoing effort to bolster the economy.

(Read more: After-hours buzz: CBS, Whole Foods, Yelp & More)

"The Fed didn't change too much in its statement," said Michael Sheldon, chief market strategist at RDM Financial Group. "While the FOMC is likely to start tapering its asset purchase program before too long, Bernanke has reminded us that he is aware of the fact that rising rates can have an effect on the economy and inflation remains low. These two factors indicate that the Fed will likely not be in a big rush unless economic data strengthens faster than expected."

Stocks traded near session highs shortly after the market open, with the Dow hitting a fresh high, boosted by a pair of better-than-expected economic reports. Stocks erased their gains soon after and chopped around in a narrow range following the Fed's widely-anticipated statement.

The Dow Jones Industrial Average slipped 21.05 points to close at 15,499.54. The blue-chip index was up more than 100 at its session high, setting a fresh intraday record of 15,634.32.

The S&P 500 erased 0.23 points to end at 1,685.72. And Nasdaq eked out a gain of 9.90 points to finish at 3,626.37. The CBOE Volatility Index (VIX), widely considered the best gauge of fear in the market, closed above 13.

Among key S&P sectors, consumer discretionary and energy led the gainers, while telecoms and utilities slid.

For the month, the Dow rallied 3.96 percent, the S&P 500 soared 4.95 percent, and the Nasdaq jumped 6.56 percent. All three major averages posted their best July since 2010.

The central bank said it will continue buying $85 billion in mortgage and Treasury securities per month. But the Fed signaled concern about higher mortgage rates and flagged the risks of inflation falling too far below its target. Additionally, the Fed said that the economy is growing only modestly, a downgrade from its previous assessment in June.

(Watch: Art Cashin:Federal Reserve 'chickened out')

Earlier in the session, data showed that economic growth in the U.S. unexpectedly accelerated in the second quarter, with the GDP growing at a 1.7 percent annual rate, according to the Commerce Department. And private employers added 200,000 jobs in July, topping economists' expectations in an encouraging sign for the labor market recovery.

The ADP report came ahead of the widely-watched government jobs data, due at the end of the week. Economists surveyed by Reuters expect nonfarm payrolls to have risen 184,000 in July.

(Read more: Big jobs numbercoming? Data firm says just 23,000)

In another upbeat sign for the economy, the pace of business activity in the Midwest picked up modestly in July. And U.S. labor costs rose in the second quarter, according to the Labor Department.

Facebook briefly traded above its May 2012 initial public offering price of $38 a share earlier in the session, fueled by positive momentum following the company's better-than-expected earnings and a new program aimed at helping small and mid-size developers distribute their games. But shares eventually reversed their losses to close in the red.

(Read more: Why the Facebook rally could end at the IPO price)

Herbalife spiked after billionaire investor George Soros took a large long position in the nutritional supplements maker, according to sources. Soros' position in Herbalife is one of his top three holdings, sources said. Meanwhile, Soros provided no comment on the position to CNBC.

JCPenney slumped more than 10 percent after the NY Post reported that lender CIT has stopped supporting deliveries from smaller manufacturers to Penney stores.

Air Products and Chemicals rallied after activist investor Bill Ackman launched his biggest bet yet, taking a 9.8 percent stake in the company, a $2.2 billion investment.

Among earnings, Comcast rallied after the cable company posted quarterly results that exceeded Wall Street forecasts as it added more Internet customers than expected and saw a more than 20 percent increase in operating cash flow at its NBCUniversal unit. Comcast is the parent company of NBCUniversal.

MasterCard jumped after the credit-card provider beat earnings expectations.

Humana gained after the health insurance provider beat earnings expectations and lifted its guidance for the year on strong growth in membership levels.

And SodaStream zipped higher after the home soda systems maker topped earnings expectations.

So far, approximately 60 percent of S&P 500 companies have posted quarterly results so far, with 67 percent of firms exceeding earnings expectations and about 55 topping revenue estimates, according to the latest data from Thomson Reuters.

Allstate, CBS, Wholefoods and Dreamworks Animation are among notable companies slated to post results after the closing bell.

—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)

On Tap This Week:

THURSDAY: Challenger job-cut report, jobless claims, PMI manufacturing index, ISM mfg index, construction spending, natural gas inventories, Fed balance sheet/money supply, auto sales, JCPenney vs. Martha Stewart closing arguments, Michael Kors shareholder mtg, Motorola Moto X launch; Earnings from AstraZeneca, ConocoPhillips, ExxonMobil, P&G, Royal Dutch Shell, Barrick Gold, Cigna, Clorox, Time Warner Cable, AIG, Kraft Foods, LinkedIn, Leap Wireless
FRIDAY: Nonfarm payrolls, personal icome & outlays, factory orders, Congress breaks for summer, Dell shareholders mtg, Detroit bankruptcy hearing; Earnings from Chevron, Toyota, Viacom

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