The report by Zona Research Inc., released Thursday, says that Netscape's Navigator has widened its lead in the business market, now residing on 60 percent of corporate desktops. The rise in Netscape's corporate market share since July is attributable to the company's decision to make the Web browser available for free, and also reflects companies' continuing belief that Navigator is a viable alternative, said Zona analyst Clay Ryder. Much of IE's gain in the overall browser market can be attributed to corporate policies mandating its use. The report, based upon data from 113 companies, shows that the remaining 40 percent are using Microsoft's Internet Explorer as their primary Web browser. For the first time since the study's inception in 1996, no company reported using any product other than IE or Navigator as its primary browser, Zona officials said. In Zona's last study of corporate browser market share, in July, Navigator was the browser of choice for 54 percent of users, compared with 45 percent for IE But while Netscape made overall gains in the corporate market, Microsoft enjoyed an advantage in one business area, thanks to its control of the desktop operating systems. Among companies that "encourage or require" the use of specific browsers -- 63 percent of respondents said they have such policies - the majority, 54 percent, say they use IE, compared with 46 percent for Navigator or Netscape's Communicator. "We believe this increase is largely due to the fact that IE 4.0 is an integral part of Windows 98, that Microsoft has continued to make inroads in the corporate marketplace, and numerous distribution agreements with [Internet] service providers and software vendors," Ryder said. While Netscape is winning the corporate battle, IE is coming on strong overall. A browser market study released last month by International Data showed that a straight-ahead comparison between all users puts Navigator on top, with 41.5 percent, to IE's 27.5 percent. But when America Online Inc.'s subscribers are factored in, IE ends up with 43.8 percent of the market, according to the IDC study. Zona officials concluded that much of IE's gain in the overall browser market can be attributed to corporate policies mandating its use. "Corporate browser policies continue to greatly impact browser use ... ," said Ryder, who added that the report shows that "84 percent of IE use as the primary browser is policy-driven." The majority of corporations are using the 4.0 versions of both Netscape's and Microsoft's products, the report said.