 Shares of Jabil Inc. JBL, -0.14 jumped 5.1 in premarket trading Tuesday, after the contract manufacturer reported fiscal fourth-quarter earnings that beat expectations, provided an upbeat outlook for the current quarter and set a 1 billion stock buyback program. Net income for the quarter to Aug. 31 rose to 315 million, or 2.25 a share, from 175 million, or 1.16 a share, in the year ago period. 