General: Should global companies never underestimate the effect?
Special: What should global companies never do?
Alternative: Should global companies always or never underestimate the effect?
Tag: Global companies should never underestimate the effect, should they? (тут уже есть отрицание в первой части вопроса (слово never), соответственно, двойного отрицания быть не может)
Subject: Who should never underestimate the effect?
