v. To exchange something for a much larger size; to increase in size substantially.
2002
The trouble is, it's not easy to be both efficient and big. As a corporation supersizes itself, it usually gets divided up into little duchies, which tend to pursue their own interests, not the company's.
1994 (earliest)
By trading up, consumers get a 32-ounce beverage and 20-percent larger fry order. In-store materials encourage patrons to trade up with the words "Super Size It!" and national television, radio and cableget the word out on the new offering.