Are Catholics considered to be a subgroup of Christians?

Answer 1

Of course Catholics consider themselves to be Christians. After all, they were the original Christian Church.

Roman Catholic AnswerThe question should be: can anyone who is not Catholic consider themselves a Christian? And the answer would be, anyone who is validly baptised and believes in the Nicene Creed in its original interpretation is a Christian, because they are part of the Catholic Church. The current usage where almost anyone can call themselves a "Christian" is to be deplored as to do that they are redefining who our Blessed Lord was and is, in His Mystical Body, which is the Catholic Church.

Answer 2

No Catholics are your Christians in the sense of the word. When Martin Luther created the Lutherans and protested the church, Protestants took the modern term Christian and coined it. When people say Christian this is referring to all followers of Christ it's just that protestants are so off the grid they still have to relate to a religion that they are derived from, Catholicism.