Stock index futures moved higher on Wednesday as commodity prices rose and investors looked ahead to a private sector employment report expected to show an easing of job losses ahead of the government's June payroll data.

But underscoring the fragile state of the economy, U.S. mortgage applications plunged to a seven-month low last week as demand for home refinancing loans tumbled 30 percent, limiting premarket advances.

Oil and commodity prices, which put pressure on stocks in the last session as they fell in tandem with a stronger U.S. dollar, headed higher as the dollar edged down and crude futures climbed 1.6 percent.

The dollar's backed up a bit and oil is back above $71 ... so that is helping the futures story now, said Art Hogan, chief market analyst at Jefferies & Co in New York.

Other data to be released on Wednesday include May pending home sales and June manufacturing figures. Between now and 10 a.m., there are going to be plenty of things to either give us pause or move us higher, Hogan said. It's going to be one of those days where any piece of incrementally good or bad news could move things pretty violently.

Automatic Data Processing (ADP) releases its June employment report at 8.15 a.m.. Economists in a Reuters survey expect ADP's data to show 393,000 jobs were lost in June, down from a May job loss figure of 532,000.

S&P 500 futures rose 6.5 points and were above 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 gained 33 points, and Nasdaq 100 futures added 9.25 points.

Food maker General Mills Inc reported a jump in quarterly net income, driven by strong sales of its cereals and dough products.

In other earnings news, Constellation Brands Inc reported earnings per share of 33 cents in the first quarter of its fiscal year.

On the data front, at 10.00 a.m., the Institute for Supply Management releases its June manufacturing index, seen as early sign into the health of the economy. Economists in a Reuters survey expect a reading of 44.5 compared with 42.8 in May.

The National Association of Realtors releases pending home sales for May, also at 10.00 a.m.. Economists in a Reuters survey expect a flat reading.

Investors will also be watching the release of U.S. automakers' June auto sales for insight into the resilience of consumers. Economists in a Reuters survey expect annualized sales of 3.33 million cars and 4.00 million trucks. In May, car sales stood at 3.35 million, and truck sales were 4.03 million.

(Editing by Padraic Cassidy)