Wall Street stocks were set for a lower open on Wednesday after weaker-than-expected manufacturing data added to evidence the U.S. economy's recovery was slowing.

The Dow was on track for a four-day decline for the first time since August. The S&P 500 closed at its lowest level in over a month on Tuesday and ended below its 50-day moving average for a second straight day.

New orders for long-lasting durable goods posted their largest decline in six months in April as aircraft and motor vehicle orders tumbled, a government report showed.

Recent weak U.S. data, including soft manufacturing figures from the Atlantic region and disappointing New York and Philadelphia Fed manufacturing surveys, pointed to a slowdown in the pace of economic growth.

It's another modestly disappointing data point in a long series of slightly disappointing data points that we've gotten in the last month. Not indicative of an economic downturn, it just kind of paints a picture that the economy is in a momentary lull, said Fred Dickson, chief market strategist at D.A. Davidson & Co in Lake Oswego, Oregon.

S&P 500 futures fell 3.1 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 lost 19 points and Nasdaq 100 futures fell 3.25 points.

American International Group Inc shares fell 3.2 percent to $28.69 in premarket trade, below the $29 offer price of the 300 million shares being sold by the U.S. Treasury and the bailed-out insurance company.

In earnings news, Polo Ralph Lauren Corp posted lower-than-expected quarterly results and said higher raw material costs and business interruptions in Japan would hurt full-year margins, sending its shares down more than 10 percent in premarket trade.

Greece's battle to win support for new austerity measures aimed at bringing its public finances under control and securing the next tranche of bailout funding also weighed on riskier assets.

Finland's parliament approved Portugal's bailout package on Wednesday.

U.S. regulators launched one of the biggest ever crackdowns on oil price manipulation on Tuesday, suing two well-known traders and two trading firms owned by Norwegian billionaire John Fredriksen for allegedly making $50 million by squeezing markets in 2008.

GE Capital is selling its A$5 billion ($5.3 billion) Australia and New Zealand mortgages books to Pepper Homeloans.

In other economic news, the OECD said a global economic recovery is on track, helped by a stronger United States, but threats ranging from high oil prices to European sovereign debt crises could yet combine to create a bout of stagflation.

(Reporting by Angela Moon, Editing by Kenneth Barry)