Integrated oil and gas companies <.GSPOILI>, oil and gas exploration and production companies <.GSPOILP> and oil & gas equipment companies <.GSPOILW> were the three biggest sector drags on the S&P, with every single company in those three indexes closing the day lower. "I guess it's not surprising that you're going to get some pullback after the move you've seen," said analyst Brad Beago at Calyon Securities. Refiners in particular were down sharply, after days of strong gains fueled by diminished capacity and rising prices, as the International Energy Agency was set to release 2 million barrels of day of oil products to the United States to help ease shortages. Among those ending lower were Valero Energy Corp. , off almost 1 percent at $108.43; Frontier Oil Corp. , off 6.5 percent at $38.50; Tesoro , down 3.6 percent at $59.05; and Sunoco , down 3.6 percent at $75.25, all on the New York Stock Exchange. "It's kind of like releasing the strategic petroleum. It's more psychological than anything else," Beago said, noting that it could take many days or perhaps longer for the IEA supplies to actually reach the United States. Even with Friday's declines, though, refiners as a sector were the biggest gainer on the U.S. stock market this week, up more than 20 percent. Investors eagerly snapped up shares of exclusively onshore producers this week as well, betting that they would take advantage of oil prices near $70 per barrel without having to bear the burden of recovery costs in the Gulf of Mexico. They also bought oilfield services shares, as extensive repair work is expected in coming months. Citigroup said in a research note Friday it believes the markets are now assuming oil at $60 a barrel and natural gas at $9 per thousand cubic feet for 2005 and 2006, up from prior estimates of $45 and $6 respectively, "due to Katrina-related speculation." PIN/Reuters