NEW YORK (AP) ¿ Standard & Poor's Ratings Services said Tuesday it cut its outlook on Koppers Holdings Inc. to "Stable" from "Positive" on weak second-quarter earnings. Earlier this month the Pittsburgh-based maker of carbon compounds and commercial wood treatment products reported a 52 percent decline in quarterly earnings. "The outlook revision reflects Koppers' weaker-than-expected operating performance in recent quarters and our expectation of continued challenging business conditions resulting from the global recession," said Standard & Poor's credit analyst Henry Fukuchi. "We expect the current economic conditions to continue to dampen operating results, particularly within the carbon materials and chemicals segment in North America and Europe." He also said he expects the company's cash flow generation to weaken. In aftermarket trading, shares fell 1 cent to $26.59.