(For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window) * Gap eyes best day in six months on upbeat forecast * Peloton sinks on U.S. govt subpoenas, bike price cuts * Futures up: Dow 0.22%, S&P 0.26%, Nasdaq 0.32% (Adds comment, details; updates prices) Aug 27 (Reuters) - Wall Street’s main indexes were set to inch higher at open on Friday ahead of Federal Reserve Chair Jerome Powell’s speech that could offer clues on when the central bank will start paring back its large stimulus program. Oil majors Exxon Mobil, Chevron Corp and Schlumberger NV rose between 1.2% and 1.4%, tracking crude prices, while big banks, including JPMorgan Chase & Co , were up about 0.4%. U.S. stocks fell from all-time highs on Thursday on concerns over developments in Afghanistan and hawkish signals from Fed officials. In an exclusive interview to Reuters, Atlanta Fed President Raphael Bostic, a voting member of Fed’s policy setting committee, said it would be “reasonable” to trim bond purchases beginning in October if strong job gains continue. Powell, who is due to speak via webcast at 10 a.m. ET (1400 GMT) at the annual Jackson Hole economic conference, may acknowledge the economy’s progress toward full employment, and likely provide hints about slowing the $120 billion in monthly asset purchases, with an announcement expected before the end of 2021. “$120 billion a month is just excessive in terms of money printing, and you’re seeing that in the inflation numbers. So there’s little choice that Powell has to execute the so-called tapering,” said Greg Swenson, founding partner of Brigg Macadam. “The market has been become really dependent on the Fed purchases and that’s something that has to be addressed, it can’t go on forever.” Data showed the Fed’s favored inflation gauge, personal consumption expenditure, rose largely in-line with estimates in July. A strong corporate earnings recovery and hopes of a vaccine-driven economic rebound have pushed U.S. stocks to record levels in recent sessions, but soaring cases of the Delta variant of COVID-19 have clouded economic outlook. The three major indexes were set for slight weekly gains, with the tech-heavy Nasdaq looking to outperform. At 8:38 a.m. ET, Dow e-minis were up 77 points, or 0.22%, S&P 500 e-minis were up 11.5 points, or 0.26%, and Nasdaq 100 e-minis were up 48.75 points, or 0.32%. Among earnings-driven moves, apparel retailer Gap Inc jumped 7.6% after it raised its full-year net sales forecast as socializing makes a comeback with easing pandemic curbs. Workday Inc added 7.8% as brokerages raised their price targets on the stock after the enterprise cloud applications company beat analyst estimates for second-quarter revenue. Peloton Interactive Inc tumbled 4.9% after it issued a profit warning and said it was being probed by U.S. regulators over an accident involving its treadmills earlier this year. (Reporting by Devik Jain in Bengaluru; Editing by Saumyadeb Chakrabarty) Our Standards: The Thomson Reuters Trust Principles.