The Dow and the S&P 500 fell on Thursday as some investors doubted that banks would sustain strong first-quarter performance as unease about the economy's health persist.

Deal speculation sent the Nasdaq higher.

Even though JPMorgan Chase & Co posted stronger-than-expected quarterly results, analysts said there remained concerns that the banking sector may be buffeted by more credit losses.

The KBW Bank Index <.BKX> fell 1.33 percent, while Wells Fargo slid more than 3 percent to $18.96.

Shares of credit card companies also took a beating following down beat broker comments. American Express

dropped 3.2 percent to $19.94, putting the stock among the top drags on the Dow. Capital One dropped 5 percent to $16.44.

The Dow Jones industrial average <.DJI> dropped 53.53 points, or 0.67 percent, to 7,976.09. The Standard & Poor's 500 Index <.SPX> fell 3.06 points, or 0.36 percent, to 849.00. The Nasdaq Composite Index <.IXIC> gained 4.97 points, or 0.31 percent, to 1,631.77.

The Nasdaq was little changed as investors bet there could be more consolidation in the technology sector after a report that Sun Microsystems is open to takeover talks with IBM .

Although CNBC reported that IBM was apparently no longer interested in a talking to Sun Micro, investors held out hope that there may be other deal activity ahead. Sun Micro shares jumped 1.6 percent to $6.23.

(Additional reporting by Ellis Mnyandu)

(Editing by Theodore d'Afflisio)