Englewood, Colo.-based Liberty Global said it would offer €35 per share for the 49.6% of Telenet it doesn't already own, a 12.5% premium to the stock's Wednesday close.

"Telenet is one of our most successful operations and a core part of our growing pan-European platform. We remain very supportive of the existing management team and employees at Telenet, all of whom have contributed to the company's success," said Liberty Global president and CEO Mike Fries in a statement.

Liberty Global, Denver media magnate John Malone's international investment vehicle, has been gradually tightening its grip on Telenet since first buying a 14% stake from rival U.S. cable investor John Callahan in 2004. At the time, Liberty Global paid $23 million for the holding.

Telenet said it would appoint an independent auditor to review the offer before commenting. The target also said it would continue preparing its own tender offer to buy back 18.2% of its shares. Telenet had originally offered to buy the shares at the same €35 price Liberty is offering but then reduced the price to €31.75 to adjust for a €3.25-per-share payout to investors in August.

Telenet said it would continue with the buyback in case the Liberty offer, which hasn't yet been formally launched, failed. Telent Thursday also increased its guidance for 2012. The company said it now expects both sales and Ebitda to increase between 7% and 8% this year after earlier forecasting between 5% and 6% growth from 2011 revenue of €1.4 billion and Ebitda of €723 million.

The company said a growth in the number of subscribers buying several of its cable, Internet and pay-TV products led to the increase.

Liberty Global said the bid must deliver a total 95% of the company for it to succeed - at that level the buyer could force out any remaining shareholders and delist Telenet.

Telent shares quickly shot up to the €35 offer price on the Brussels exchange after being suspended for an hour in the morning pending the announcement.

The unsolicited offer follows a May takeover agreement between Liberty's German Kabel Deutschland Holding AG unit and the creditor-owners of peer Tele Columbus AG. The Tele Columbus takeover gave Kabel Deutschland 1.7 million customers in parts of the former East Germany and was worth €618 million.

Liberty Global is being advised by Morgan Stanley and Freshfields Bruckhaus Deringer LLP.