When Coca-Cola consolidated marketing into a new "chief growth officer" (CGO) role in March, it followed previous Fortune 100 companies in doing so — Hershey's announced Mary Beth West had joined as CGO earlier that month, while Kellogg gave the same job title to Clive Sirkin in 2015.

According to consultancy Forrester, this is a trend that will continue next year. "In 2018, we expect CMOs to fall under even more pressure to drive growth — or step aside while someone else takes the reins," its "Predictions 2018" report states.

The new CGO roles will include marketing, strategy and commercial responsibility, with Forrester suggesting eight more Fortune 100 companies will appoint such positions in 2018. It predicts that CMOs will "grow or go" in the coming year, with chief executives expected to put marketers under pressure to reduce advertising spend.