* HP jumps after raising 2013 outlook
* China manufacturing data shows contraction
* Futures off: Dow 128 pts, S&P 15.8 pts, Nasdaq 22.5 pts
By Chuck Mikolajczak
NEW YORK, May 23 (Reuters) - U.S. stocks were set for a lower open on Thursday, with the S&P 500 on track for its first back-to-back daily drop in a month, amid investor concerns the U.S. Federal Reserve's stimulus may be scaled back sooner than hoped and over weak data in China.
The S&P 500 posted its biggest decline in three weeks on Wednesday, after minutes from the latest U.S. Federal Reserve meeting showed some officials were open to tapering large-scale asset purchases as early as at the June meeting.
The minutes came in the wake of comments earlier in the session by Fed Chairman Ben Bernanke, who said the Fed could scale back the pace of its bond purchases at one of the "next few meetings" if the economic recovery looked set to maintain forward momentum.
Adding to selling pressure, China's flash HSBC Purchasing Managers' Index for May fell to 49.6, slipping under the 50-point level which indicates expansion for the first time since October. That raised concerns the recovery in the world's second-largest economy has stalled and a sharper downturn may be on the horizon.
"We are kind of in a situation where all news is bad news in a way when the Fed starts to talk," said Peter Jankovskis, co-chief investment officer at OakBrook Investments LLC in Lisle, Illinois.
"They are pretty well maxed out...so you are kind of here waiting on the end game."
Separately, data in Europe showed that while the downturn across euro zone businesses eased slightly in May, the bloc's economy is likely to contract again in the second quarter.
In a bright spot, the number of Americans filing new claims for unemployment benefits dropped 23,000 to a seasonally adjusted 340,000, slightly better than expectations for a decline to 345,000, a report showed.
But U.S. manufacturing slowed for a second straight month in May, as the Markit Purchasing Managers Index fell to a seven-month low of 51.9 in May from 52.1 the previous month.
The benchmark S&P index has jumped 16.1 percent since the start of the year, boosted by slowly improving U.S. economic data and stimulus measures by central banks around the globe.
S&P 500 futures dropped 15.8 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones (DJI: ^DJI - news) industrial average futures lost 128 points, and Nasdaq 100 futures slumped 22.5 points.
Later in the session at 10:00 a.m. EDT (1400 GMT), housing market data will be released, in the form of the Federal Housing Finance Agency's home price index for March and new home sales for April.
Economists in a Reuters survey forecast new home sales to show a total of 425,000 annualized units compared with 417,000 in March.
Hewlett-Packard Co jumped 10.5 percent to $23.45 in premarket trade after the computer maker raised its 2013 earnings outlook after quarterly results beat low expectations.
Ralph Lauren Corp shares fell 3.8 percent to $181 before the opening bell after the fashion company reported sales that fell below its own projections.
Hormel Foods Corp reported a lower quarterly profit due to costs related to its Skippy acquisition, and higher grain costs and lower turkey meat prices at its Jennie-O Turkey stores.