Accordingly, the company spread its hydrocarbons
procurement among petroleum- and coal-based feedstocks;
balanced its geographic base among Middle
Eastern, African, North Sea, North American, and
Latin American sources; changed its contracts-tospot-
purchases ratio; optimized its make-or-buy mix
by integrating backward; and began to rely on wholly
owned subsidiaries for a bigger share of its feedstock
requirements. In addition, a corporate-level review
revealed attractive trade-off and substitution opportunities,
which the corporation soon set about exploiting,
once it had changed and upgraded its purchasing
organization and systems in order to do so.