Macy’s Inc on Tuesday decided against a push by an activist investor to spin off its online business and forecast better-than-expected annual sales after a bumper holiday season, during which it kept its shelves well-stocked. The department store chain also announced a $2 billion share buyback plan and raised its quarterly dividend by 5 percent, sending its shares up more than 8 percent in premarket trading. Macy’s posted a 12 percent sales jump in its digital business, with the company’s valuation rising to $7.7 billion from $6.9 billion in October last year when activist investor Jana Partners urged the company for a spinoff. Jana had argued in its presentation that the online business could be worth a multiple of Macy’s market capitalization. Earlier this month, Jana said it cut its holdings in Macy’s by 84 percent in the last months of 2021, before which it held a 1.5 percent stake. …