Google Inc. (GOOG) is down near 1% and under selling pressure in afternoon trading after a new report by Internet tracking firm comScore showed erosion in Google’s search market share for the second consecutive month, while rivals Microsoft (MSFT) and Yahoo! (YHOO) posted gains. Google opened down .51 at 2.50, made a brief morning run to a session high of 7.72, and then fell back, testing its session low of 1.62 following release of the report. ComScore Inc. said that Google’s market shares for Internet search fell in May to 63.7%. At the same time, Yahoo and Microsoft both gained during that period with a combined 30.4%, the report said. Google shares are down .41, or 0.91%, to 2.40. Microsoft shares are up 1.52%, or 0.37, to .38. Yahoo shares are up 0.40%, or {video_description}.06, to .16.