Stock index futures fell on Friday as concerns over Spain's rising borrowing costs resurfaced and after disappointing Chinese growth data, and banks fell after quarterly results.

JPMorgan Chase & Co shares fell alongside first quarter profit, and Wells Fargo lost more than 2 percent after results.

Earlier reports showed Spanish banks borrowed heavily from the European Central Bank in March, sending benchmark yields higher, while China's economy grew at its slowest pace in nearly three years.

The Chinese GDP number was weaker than expected and everyone had used it as an excuse to rally yesterday, said Peter Boockvar, equity strategist at Miller Tabak & Co in New York.

JPMorgan is down after what seemed a better than expected quarter, we're seeing further weakness in Spain and Europe we should give some of (the previous gains) back, Boockvar said.

The S&P 500 added more than 2 percent in the two previous sessions as immediate concerns over rising yields in Spain and Italy ebbed and on bets the Chinese GDP data would surprise on the upside.

S&P 500 futures fell 6.3 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 38 points, and Nasdaq 100 futures lost 11.75 points.

S&P futures traded above their 50-day average throughout the session, after closing below that level twice earlier this week.

Basic materials and energy shares could be pressured as copper and oil prices dipped after the Chinese data. Still, some hoped the soft data was a sign Beijing could ease monetary policy further to support the economy.

On Thursday, the Dow Jones industrial average <.DJI> jumped 181.19 points, or 1.41 percent, to end at 12,986.58. The S&P 500 Index <.SPX> gained 18.86 points, or 1.38 percent, to 1,387.57. The Nasdaq Composite <.IXIC> climbed 39.09 points, or 1.30 percent, to 3,055.55.

(Reporting by Rodrigo Campos; Editing by Theodore d'Afflisio)