LONDON (Reuters) -An OPEC technical panel invited a top financial market dealer to give a presentation this week which painted a bearish outlook for the oil market, according to materials from the presentation seen by Reuters. "Market sentiment had been fragmented for much of this year, but the evidence is that there has been a recent shift in collective sentiment to bearish as we head towards the end of the calendar year," one of the presentation slides by Onyx Capital Group showed. OPEC - the Organization of the Petroleum Exporting Countries - did not immediately reply to a request for comment.