In August, though, IE started taking some market share back. Chrome had increased its lead in July, 33.81% to IE's 32.04% but IE closed the gap in August. By the end of the month, Chrome lost a bit, to 33.59% and IE had gained some to reach 32.85%.
Some of IE's gains were at Chrome's expense, but the real loser has been Firefox. The long time number two Web browser dropped from 23.73% in July to 22.8% in August.
As to why IE is making a come-back... I can only speculate. There has been no new release of IE, well Chrome, as always keeps popping out new releases every six weeks. Thus, the latest IE for XP is still IE 8, for IE 9 is still Windows 7's default browser , while Chrome is now up to Chrome 21 with 22 soon to come.
You might guess that the gain was due to IE 10, which is the released to manufacturing (RTM) Windows 8's default Web browser, but a closer look at StatCounter's data shows that IE 10 still doesn't have any market share worth mentioning. The biggest gain by version is for IE 9, so perhaps what we're seeing is Windows XP users moving to Windows 7 and giving IE 9 a fair shake.