Generously grease 12-cup Bundt® pan. In large bowl, combine 2 1/2 cups of the flour, cocoa, sugar, salt, baking soda and yeast; mix well. In small saucepan, heat buttermilk and butter until very warm (120 to 130°F.). Add warm liquid and eggs to flour mixture; beat at low speed until moistened. Beat 3 minutes at high speed.
By hand, stir in remaining 1 cup flour and 1 1/2 cups chocolate chips. Spoon dough evenly into greased pan. Cover with plastic wrap and cloth towel; let rise in warm place (80 to 85°F.) until light and doubled in size, 30 to 40 minutes.
Heat oven to 350°F. Uncover dough; bake 35 to 45 minutes or until toothpick inserted near center comes out clean. Immediately invert bread onto wire rack; remove pan. Cool 45 minutes or until completely cooled.
Place remaining 1/2 cup chocolate chips and oil in resealable food storage freezer plastic bag; seal bag. Knead bag to evenly distribute oil. Microwave on HIGH for 30 to 60 seconds or until melted. Cut small hole in bottom corner of bag. Squeeze bag to drizzle melted chocolate over cooled bread.