Wall Street stocks were set for a lower open on Thursday as worries about higher inflation and signs of job market weakness kept investors cautious.

The S&P index futures added to losses after data showed an unexpected rise in weekly jobless benefits claims to back above the key 400,000 level.

Separately, the government said U.S. core producer prices rose slightly faster than expected in March, pointing to increased inflation pressures.

Risk appetite retreated on fears of a tighter money policy in China after a media report suggested inflation figures there will be higher than expected in March.

The initial focus today will be more on earnings and the worldwide growth and inflation issues, but this number (jobless claims) could add some negative bias and create additional selling pressure, said Brian Lazorishak, portfolio manager at Chase Investment Counsel in Charlottesville, Virginia.

Investors worried corporate earnings could be hurt by supply chain disruptions arising from the earthquakes in Japan.

It's the cautious guidance from companies due to concerns about inflation and Japan that are going to weigh on investors, said Peter Cardillo, chief market economist at Avalon Partners in New York.

I see the market trading within the 3-4 percent range from the upper end to the lower end in this earnings season. I don't see it as a catalyst to move the market much higher.

Google is scheduled to release results after markets close on Thursday, with analysts expecting to see a 25 percent year-on-year increase in net revenue to $6.32 billion and earnings per share of $8.10, up from $6.76 a year earlier.

S&P 500 futures fell 8.4 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 industrial average futures fell 52 points and Nasdaq 100 futures lost 12.50 points.

In a frenzy to protect itself at the start of the credit crisis, Goldman Sachs Group Inc sold mortgage-linked derivatives to clients at inflated prices and misrepresented the nature of the deals, documents released by a Senate subcommittee said. Goldman Sachs shares fell 1.6 percent to $157.60 in premarket trade.

Commodities trader Glencore outlined its initial public offering of up to $12 billion, including plans for a May debut that will boost its firepower for acquisitions and make paper millionaires of its partners.

Shares of Supervalu Inc , the third-biggest supermarket chain by sales, rose 13 percent to $10.24 in solid volume in premarket trade after results.

U.S. regulators are probing whether major banks colluded to manipulate a global benchmark interest rate before and during the financial crisis, the Wall Street Journal reported, citing people familiar with the situation.

Suppliers to Apple Inc have begun production of white iPhones after a delay of almost 10 months, two people familiar with the situation said on Thursday.

(Reporting by Angela Moon, additional reporting by Ryan Vlastelica; Editing by Kenneth Barry)