NEW YORK, July 30 (Reuters) - U.S. stocks ended mostly higher on Tuesday following gains in technology shares and stronger-than-expected earnings from Pfizer, but a selloff in the potash sector limited the advance.
The Dow Jones industrial average wavered at the close - initially showing a gain of 3.07 points, or 0.02 percent, at 15,525.04 - and then dipping 1.38 points, or 0.01 percent, to end unofficially at 15,520.59. The Standard & Poor's 500 Index rose just 0.63 of a point, or 0.04 percent, to finish unofficially at 1,685.96. The Nasdaq Composite Index advanced 17.33 points, or 0.48 percent, to close unofficially at 3,616.47.