One of Yahoo’s top executives has jumped ship and joined Square

One of the top lieutenants in Silicon Valley is leaving the side of one high-profile Internet executive in Marissa Mayer to join another, Jack Dorsey. Jacqueline Reses is departing Yahoo! Inc., where she had been chief development officer, to join Dorsey’s Square Inc., helping boost the startup’s executive team while dealing a blow to the Web portal, according to people familiar with the matter, who asked not to be identified as the matter is private. Reses’ role changed earlier this year when she shifted her focus to Yahoo’s spinoff of its stake in Alibaba Group Holding Ltd. that is worth about $27 billion, a person familiar with the matter said in July. The arrival of Reses comes after Dorsey was this month named permanent chief executive officer of Twitter Inc., a role he also holds at Square ahead of its initial public offering. Adding her leadership could help lighten the load for Dorsey amid concerns about his dual responsibilities.