People with AB negative blood type account for 1 percent of the population, according to Oneblood.org. This is very rare due to the genetic components that must come together to create a person with this blood type. A person with AB negative blood possesses both A and B antigens.
Additionally, people with AB negative blood are considered Rh negative. Children with this blood type must be born to parents who are both Rh negative, which is a recessive gene. Considering that less than 20 percent of the population has Rh negative blood, and even fewer are AB negative, a person with AB negative blood type is rare.