Seed agronomists often talk about “racehorse” hybrids (RH) and suggest they are high yielding and require extra good growing conditions to express their high yield potential. Other terms used by company seed agronomists to describe RH hybrids include “offensive/defensive” and “fix/flex” hybrids. They suggest planting RH hybrids on the best, most productive fields. We wondered if we could identify RH hybrids from yield tests and if so how much better do they perform compared with other hybrids under high yielding conditions? And how do they perform when growing conditions are not as good for corn growth and yield?