ABUJA: Nigerian stocks climbed to a new 2-1/2 year high on Tuesday, extending gains for the seventh session after its biggest listed firm, Dangote Cement, on Monday announced plans to buy back some of its shares this month. The all share index gained 1.2% to 37,893.61 points, a level last reached in July 2018. Dangote Cement, which accounts for a third of market value, rose 6.34%.