Mondelez International Inc. said it is making investments to maintain the ground it gained on competitors to manage the ground it gained on competitors last year as shoppers bought more of its snacks while they spent time at home during the pandemic.The Chicago-based maker of Oreos and Triscuits said Thursday that comparable sales increased 3.2% annually in the fourth quarter, in line with expectations. Sales growth by that measure moderated somewhat from earlier in pandemic, especially in North America. Shares dropped 1% to $56.50 Thursday afternoon. But Mondelez said it had increased market share in businesses such as cookies and crackers in the US and chocolate in the UK.