It's merely a difference in titles -- in the UK it's often 'managing director' or some variant. Here in North America, it's CEO. Size is irrelevant: it just so happens that is the title on my shares, thus I adhere to it.

I go by 'Chief Nerd Wrangler' nonetheless, as it's more appropriate of a job description. It still doesn't make it any less of a janitorial position.