Your comment is missing the point that you can do all of these things at once. They could easily put 80% into safe assets / employee 401ks, new project funds et

Your comment is missing the point that you can do all of these things at once. They could easily put 80% into safe assets / employee 401ks, new project funds etc. and then spend 20% on buy backs. The focus on buy backs is due to the fact that American business ties executive bonuses to share valuation.