(For a live blog on the U.S. stock market, click or type LIVE/ in a news window) * Weekly jobless claims at 885,000 vs 862,000 in prior week * Fed maintaining easy monetary policy helps stocks * Futures up: Dow 0.3%, S&P 0.5%, Nasdaq 0.5% (Adds comment, updates prices) Dec 17 (Reuters) - Wall Street’s main indexes were set to gain on Thursday on increased optimism over a coronavirus stimulus bill, while an unexpected rise in weekly jobless claims pointed to further economic stress from the COVID-19 pandemic. Negotiations were underway in Congress late on Wednesday over the details of a $900 billion aid bill, with top Democrats and Republicans sounding more positive than they have in months on a fresh response to a crisis that has killed more than 304,000 Americans and thrown millions out of work. The number of Americans filing first-time claims for jobless benefits unexpectedly increased last week as a relentless surge in new coronavirus infections hobbled business operations and hurt hiring trends. U.S. S&P 500 E-minis were up 17 points, or 0.46%, at 08:36 a.m. ET, Dow E-minis were up 102 points, or 0.34%, while Nasdaq 100 E-minis were up 60.25 points, or 0.48%. The Federal Reserve kept interest rates at near-zero levels on Wednesday and vowed to keep funneling cash into financial markets over the long term. Equity markets have been among the main beneficiaries of accommodative policy through the virus outbreak. “We have been waiting on this stimulus for months now, but we also have the Federal Reserve buying almost a trillion and a half dollars worth of assets a year,” said Mike O’Rourke, chief market strategist at JonesTrading.