DOW JONES NEWSWIRES A filing Wednesday showed hedge fund Taconic Capital Advisors accumulated a 5.1% stake in business-software maker CA Inc. (CA). Shares were up 6% at $22.19 after hours. Through the close, the stock has fallen 15% in the last year, worse than the market at large. The filing, with the Securities and Exchange Commission, said Taconic acquired the shares because it believes they're undervalued. CA, which makes software for mainframe and other corporate computers, could increase its stock value by increasing cash returns to shareholders, streamlining capital structure and improving margins in its enterprise segment, Taconic said. It also suggested a senior management compensation structure based primarily on total shareholder returns rather than the current emphasis on absolute growth metrics. The filing also said Taconic has previously had, and plans to continue to have, talks with CA's management and the board of directors. The company has been watching its costs carefully in recent years. In its latest quarterly results, earnings rose 6.3% as revenue increased in all three of its segments. -By Joan E. Solsman, Dow Jones Newswires; 212-416-2291; joan.solsman@dowjones.com