Holding operacional - Tradução em português

Maybe this isn't a genuine English question (I think it's more like an Economics one) but I'm sure somebody here will be able to explain me. What does "holding" mean exactly in the following sentence? :

"A privatização do Sistema Telebrás ocorreu em 1998, mas a holding não operacional continuou a existir."

Source: http://g1.globo.com/Noticias/Economia_N ... 56,00.html

Thank you in advance!