Yahoo! Inc. Chief Executive Officer Marissa Mayer hired KenGoldman to succeed Tim Morse as chief financial officer, making herbiggest management change yet after taking the reins of thestruggling Web portal.

Goldman was previously chief financial officer at Fortinet Inc.,a provider of computer-network security. His appointment iseffective Oct. 22, while Morse, who joined in 2009, is leavinglater this year, Sunnyvale, California-based Yahoo said in astatement yesterday.

Mayer, who joined in July, is realigning leadership in her driveto reverse three years of declining revenue and market share lossesto Facebook Inc. and her former employer, Google Inc. She may seekto impose fiscal discipline by hiring Goldman, who has helped cutcosts and improve oversight at Silicon Valley companies over thepast three decades, said Erik Suppiger, an analyst at JMPSecurities LLC in San Francisco.