El Economista reports that once this happens it will have a 29.9% stake, just short of the 30% required by law to launch a total take-over.
Its offer for the additional stake, equivalent to 26,620,000 shares, amounts to €7.75 per share.
Zegona plans to receive support for the capital increase with which to pay for the offer when it holds its AGM in the last week of December.
As previously reported by Broadband TV News, Zegona has close links with Virgin and is likely to introduce the Virgin brand in Spain.
It launched a bid to increase its stake in Euskaltel in October.