DETROIT—General Motors Corp.‘s top U.S. marketing executive said today he does not foresee further big cuts in the automaker’s sports sponsorships as it balances a cash shortage with the need to market its products. Mark LaNeve, vice president for North American marketing, said GM is still looking at every penny of its advertising budget as it tries to cut expenses and prove it is viable in order to keep $13.4 billion in government loans.