Although still the market leader, Netscape's Navigator lost nine percentage points of market share in the U.S. browser market in the first half of 1998, according to a new report published by International Data Corporation (IDC), Framingham, Mass. Microsoft's Internet Explorer gained just under five percentage points of market share in the same period. America Online (AOL) remained stable from the end of 1997 to mid-1998 in the home segment. "The results of this third IDC survey tracking Web browser market share show a dramatic shift toward Microsoft Internet Explorer by midyear 1998," says Joan-Carol Brigham, research manager, Internet and e-commerce strategies. "It appears that Microsoft's current battle with the U.S. government and Netscape's software giveaway have had little effect in keeping Netscape's market share from eroding." This research bulletin reveals Microsoft continues to make steady progress in each user segment, although its greatest challenge still is within large- and medium-sized businesses. AOL has made good progress in small businesses, apparently picking up where Netscape lags, according to IDC. "Six months ago, Netscape continued to lead and made gains with small-business users," says Brigham. "As of June 1998, the company has lost almost 10% share with this population. And although Netscape has stated in its most recent fiscal quarterly report that it continues to gain large business customers, medium-sized and large business segment, our research shows usage of Navigator has dropped almost 9% in the last six months. Microsoft's weakness remains in the medium-sized and large business segments, where it has made minimal gains. This is clearly a Netscape opportunity."