<p>The S&P 500 suffered its worst day since June on Tuesday (September 25), pulled lower by Caterpillar Inc after it cut its profit outlook.<br /><br />Technology shares came under pressure after a second day of weakness for Apple Inc, the world's most valuable public company.<br /><br />Shares fell 2.5 percent to $673.54 (USD) as the company sold out of its initial supply of the new iPhone, raising concerns about keeping up with demand.<br /><br />Caterpillar, the heavy equipment maker, said on Monday (September 24) sluggish global growth was responsible for reduced estimates. Other companies to recently cut expectations include FedEx Corp and Norfolk Southern.<br /><br />Shares of Caterpillar were the biggest weight on the Dow for a second day and ended down 4.2 percent at $87.01. That was the stock's biggest daily percentage drop since May.<br /><br />The Dow Jones industrial average was down 101.37 points, or 0.75 percent, at 13,457.55. The Standard & Poor's 500 Index was down 15.30 points, or 1.05 percent, at 1,441.59, its fourth day of losses. The Nasdaq Composite Index was down 43.06 points, or 1.36 percent, at 3,117.73.</p>
