* TSX down 42.04 points, or 0.4 percent, at 11,391.18 * Index down nearly 8 percent in May * Mining, energy shares lead losses * U.S. data, Spain stoke investor fears * CGI up nearly 13 percent after Logica deal By Jon Cook TORONTO, May 31 (Reuters) - Canadian stocks dipped on Thursday, led lower by mining and energy issues, as disappointing U.S. data signaled the economy of Canada's largest trading partner may have stalled and as fears lingered about the state of the euro zone economy. Six of Canada's 10 main sectors were down. Declines were led by the heavyweight materials and energy groups, which both fell nearly 1 percent as oil, gold and base metals prices slumped. "Just when you think they can't go any lower, they go punishingly lower," said Barry Schwartz, vice president and portfolio manager at Baskin Financial Services. The most influential movers on the downside included top fertilizer producer Potash Corp, which fell 1.1 percent to C$40.17, copper miner Teck Resources, down 1.7 percent at C$30.75, Suncor Energy, which dropped 1 percent to C$27.75, and Canadian Natural Resources, falling 1.2 percent to C$29.50. The market has been preoccupied with the euro zone debt crisis, but on Thursday a slew of soft data raised doubts about the strength of the U.S. recovery. A report by private payrolls processor ADP showed private employers created 133,000 jobs in May, fewer than the expected 148,000, while new claims for unemployment benefits rose by 10,000 for the fourth straight weekly increase. The data comes ahead of Friday's key payrolls report. Adding to the negative tone, the Institute for Supply Management-Chicago business barometer declined to 52.7 from 56.2 in April, its lowest level since September 2009 and below Wall Street expectations. At 11:11 a.m. (1511 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 42.04 points, or 0.4 percent, at 11,391.18. The index has shed nearly 8 percent in May. Investor weariness with regards to Europe was evident on Thursday as worries over Spain fueled demand for safe havens, pushing Treasury debt yields to at least 60-year lows. Despite good second-quarter results from Canadian Imperial Bank of Commerce and National Bank of Canada, the Canadian financials index was flat. CIBC shares jumped 1.7 percent to C$71.56 after it reported a 6 percent increase in quarterly income, topping estimates, on higher volumes at its retail and business banking operations. National Bank shares rose 0.4 percent to C$73.40 after the Montreal-based bank said its quarterly core profit rose a stronger-than-expected 6 percent and raised its quarterly dividend. "Growth is getting slower, but that doesn't mean that corporate profits are going to fall off the table," said Schwartz. There were some hopes that the European Central Bank may step in to help ease the pressures in financial markets until EU leaders can agree measures to tackle the structural problems at the root of the current crisis. But ECB President Mario Draghi, speaking to the European Parliament, has moved to rule this out. In addition, the latest Greek poll showed Greece's conservative pro-bailout New Democracy party has a slim lead in the run-up to the June 17 election that could decide whether the country remains in the euro zone. In one of the few bright spots, Canada's information and technology sector jumped 3.4 percent on news that CGI Group Inc agreed to buy Anglo-Dutch IT services firm Logica for $2.64 billion on Thursday. CGI's shares spiked nearly 13 percent to C$23.71.