I
would have underperformed
you
would have underperformed
he / she / it
would have underperformed
we
would have underperformed
you
would have underperformed
they
would have underperformed
I
would have been underperforming
you
would have been underperforming
he / she / it
would have been underperforming
we
would have been underperforming
you
would have been underperforming
they
would have been underperforming