Stock index futures pointed to a fall of more than 1 percent at the open on Monday as a Spanish government bailout of a local bank refocused attention on a European debt crisis, which investors fear could derail the global economy.

The Bank of Spain said Saturday it took over Spanish savings bank CajaSur after a planned merger with another small lenders failed. CajaSur accounts for nearly 0.6 percent of assets in Spain's financial system.

Although a relatively small bank, investors fear the bailout could be a sign of more problems to come that could lead to a wider banking and credit crisis in a region already struggling to reduce high public deficits. The euro fell sharply early Monday.

Banking shares, which rallied strongly in the last session, were weaker in premarket trade. Bank of America Corp fell 0.1 percent to $15.97, Wells Fargo & Co fell 1.4 percent to $29.70, and JPMorgan Chase & Co fell 0.4 percent to $39.90.

It has refocused people's attention on the bigger picture question of whether or not this is merely a sovereign debt issue or something more systemic across Europe and potentially across the broader financial system, said Craig Peckham, equity trading strategist at Jefferies & Co in New York.

Campbell Soup Co posted a better-than-expected profit on higher sales in its key U.S. soup market, helped by increased promotional spending, and forecast full-year earnings at the high end of its target.

S&P 500 futures fell 9.9 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 dropped 73 points, and Nasdaq 100 futures lost 9 points.

The S&P 500 has entered a technical correction, falling more than 10 percent since a peak on April 23, as Europe's troubles have rattled markets. Investors are watching for the S&P 500 to close beneath the May 6 flash crash intraday low of 1,065.79, which may signal further losses.

Concerns about Europe's debt troubles overshadowed comments from a Chinese government researcher that a new property tax there would not be realized within the next three years. The comments, reported in a local paper, were later denied, but Chinese shares rallied more than 3 percent.

Monday brings U.S. existing home sales data for April, due at 10 a.m., at a time when some have begun to question the strength of the U.S. economy. Investors also fear the expiration of a tax credit for home buyers could undermine the housing market's recovery. Existing home sales are seen rising 5.9 percent to 5.63 million units after growing by 6.8 percent in March, according to a Reuters poll, with forecasts between 5.42 million and 5.80 million.

(Editing by Padraic Cassidy)