The S&P 500 index continued to rally toward the 1,400 level and was on course to post its best week in over a month on Thursday after data showed the U.S. economy continuing to improve.

Shares in Apple Inc hit a new all time high above $600 in early trading, with some analysts predicting the stock will move to $700 within 12 months.

Trading was volatile at the start of quadruple witching, the expiration and settlement of four types of equity futures and options contracts.

These are new highs for the move so we're pushing another leg up here, said Frank Lesh, a futures analyst and broker at FuturePath Trading LLC in Chicago. The market is trying to run to 1,400 here and I would be surprised if we don't.

Labor Department data showed new claims for unemployment benefits fell back to a four-year low last week, and producer prices, excluding food and energy, were contained.

The Dow Jones industrial average <.DJI> rose 14.42 points, or 0.11 percent, to 13,208.52. The S&P 500 Index <.SPX> gained 3.86 points, or 0.28 percent, to 1,398.14. The Nasdaq Composite <.IXIC> added 11.12 points, or 0.37 percent, to 3,051.85.

The 1,400 level would mark the highest level for the S&P 500 in nearly 4 years.

The S&P 500 snapped a five-day winning streak on Wednesday after advancing nearly 4.0 percent during the run, as investors found little reason to extend a rally that took the benchmark index to four-year highs. But the index is up 1.9 percent this week, its best since early February.

Manufacturing data in New York and the mid-Atlantic region also improved, according to regional Federal Reserve surveys.

If you looked at all the economic news today it actually came in better than expected, but the market is exhausted - it went all the way up to close to 1,400 and stalled, said Ken Polcari, managing director at ICAP Equities in New York.

Apple stock hit a new all-time high at $600.01, up nearly 2.0 percent from the previous day's close and up nearly 60 percent since mid-Decmeber.

The stock has been more volatile recently and on Thursday traded in a wide range between a fall of 0.9 percent and a rise of 1.8 percent. The stock last traded up 0.1 percent at $590.32.

The CBOE Apple VIX index <.VXAPL>, which tracks options on Apple's stock, leapt 16.5 percent on Thursday and is up 70 percent over the last two days, hitting its highest level since November. The move could be an indication of more volatility ahead.

Semiconductors moved higher, led by Advanced Micro Devices Inc , which jumped 5 percent to $8.15 after Jefferies upgraded the stock to a buy rating. The Philadelphia Semiconductor Index <.SOX> gained 1.3 percent.

Ross Stores Inc reported a higher profit for the holiday quarter as shoppers sought out popular clothing brands at discount prices, and the off-price chain forecast respectable sales and profit gains for this fiscal year. Shares dropped 1.7 percent to $55.63. The Morgan Stanley retail index <.MVR> lost 0.2 percent.

Three initial public offerings made their debuts on Thursday: cloud computing-based software company Demandware Inc , analog chipmaker M/A-Com Technology Solutions Holdings and Allison Transmission Holdings .

Demandware surged 49.6 percent to $23.94, M/A-Com advanced 5.7 percent to $20.07 and Allison Transmission rose 1.1 percent to $23.26.

(Editing by Padraic Cassidy) (This story corrects typo in first paragraph)