By Adam Haigh June 18 (Bloomberg) -- U.S. stock-index futures fluctuated, with the Standard & Poor’s 500 Index poised for second week of gains, as former Federal Reserve Chairman Alan Greenspan said the U.S. may soon face higher borrowing costs. Newmont Mining Corp. and Freeport-McMoRan Copper & Gold Inc. led a decline among raw-material producers as copper dropped in London. Southwestern Energy Co. may retreat after Goldman Sachs Group Inc. removed the shares from its “conviction buy” list. Transocean Ltd., the owner of the Deepwater Horizon rig involved in the largest U.S. oil spill, rallied 5 percent in Germany. Futures on the S&P 500 expiring in September lost 0.1 percent to 1,111 as of 7:17 a.m. in New York, after earlier rising 0.2 percent. Dow Jones Industrial Average futures fell 0.1 percent to 10,367, while Nasdaq-100 Index futures rose less than 0.1 percent to 1,910. “Markets will remain constrained because consensus growth estimates are already very optimistic” for company earnings, said Georgina Taylor, an equity strategist at Legal & General Investment Management in London, which oversees $482 billion. The S&P 500 has rallied 2.2 percent so far this week, building on last week’s 2.5 percent gain. The benchmark gauge tumbled 14 percent from a 19-month high on April 23 through June 7 as concern grew that Europe’s debt crisis will derail the economic recovery and BP Plc’s leaking well triggered the worst oil spill in U.S. history. The index has since rebounded 6.2 percent. Pending Crisis Greenspan said the U.S. may soon face higher borrowing costs on its swelling debt and called for a “tectonic shift” in fiscal policy to contain borrowing. “The federal government is currently saddled with commitments for the next three decades that it will be unable to meet in real terms,” Greenspan wrote in an opinion piece posted on the Wall Street Journal’s website. The “very severity of the pending crisis and growing analogies to Greece set the stage for a serious response.” Price swings and trading volume may be greater than average today because futures and options contracts on indexes and individual stocks expire at the close of trading. So-called quadruple witching occurs once every three months. Copper Falls Newmont Mining dropped 0.6 percent to $59.31 in German trading. Freeport McMoran lost 0.5 percent to $65.45. Copper fell more than 1 percent in London and headed for a weekly decline. Southwestern Energy may move after Goldman Sachs removed the shares from its “conviction buy” list. Transocean rose 5 percent to $51.91 in German trading amid signs BP is catching more of the oil gushing into the Gulf of Mexico. BP captured 18,600 barrels of oil from the leaking well on June 16, a 78 percent increase from the previous day and the most since the spill began in April. BP shares rallied 2.5 percent to 368.75 pence in London, bringing its two-day rebound to 9.4 percent. Smart Modular Technologies Inc. may move after forecasting fourth-quarter sales of at least $200 million, beating the average analyst estimate of $186.4 million. CTC Media Inc. may climb after UBS AG upgraded shares of the U.S.-listed Russian television network to “buy” from “neutral.” Shares of Smart Modular and CTC didn’t trade in Europe. To contact the reporter on this story: Adam Haigh in London at ahaigh1@bloomberg.net.

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