WSJ shares some of Microsoft's tax tricks to keep earnings in low-corporate-tax counties like Ireland.

Last month, two Dublin-based Microsoft subsidiaries -- Round Island One Ltd. and Flat Island Co. -- revamped their shareholding structure and applied to the Irish government to adopt "unlimited liability" status. That would allow the units to avoid filing detailed public statements of their accounts, government records show. But the change creates added risk for Microsoft in case either unit faces bankruptcy or a lawsuit.

The move follows several months of scrutiny of Microsoft in Ireland, as well as moves in Washington against the tax benefits the Redmond, Wash., software giant enjoyed by transferring the revenue and assets to Ireland. Microsoft's practice and the related tax benefits were disclosed in a Nov. 7 article in The Wall Street Journal. Ireland taxes corporate income at a flat rate of 12.5%, while the official U.S. rate is 35%.

Round Island One controls more than $16 billion of assets, most of it intellectual-property rights managed by Flat Island. A company spokesman said the change in status, reported by the Irish Times on Thursday, is "part of our strategy to facilitate and support future business growth." The spokesman said the firm's primary operational subsidiary in Ireland, Microsoft Ireland Operations Ltd., "will continue to publicly file its financial statements."