The CIO or chief information officer is usually responsible for IT. This is a role which only the very largest companies tend to have so we have not put a turnover limit on this mailing list.
Many companies which use the c-suite job titles have their origins in the USA and it is difficult to strip out their UK turnover from their published global turnover. For some of these companies we have no turnover or number of employees figures, so selecting them by c-suite job titles is a good way to get round this problem.