Tactical marketing concepts grew out of the need for brands to provide a more individualized execution than was possible with most co-op programs. In traditional co-op advertising, the marketer reimburses the retailer or pays them all or part of the cost of the advertising or promotion. As retailers became more and more powerful through consolidation and the formation of buying groups and with the expansion of national chains via mergers, they began using co-op advertising as a profit centre to offset their operating costs. Frequently funds went to increasing store margins and other non-advertising functions. With an increasing power advantage, retailers began forcing marketers to participate in retailer initiated programs which may or may not have been to the advantage of the marketer or its brands. In effect, the marketer had lost control of co-op programs to the retailer.