Mr Denis O'Brien's eIsland consortium confirmed this morning it had posted its formal offer for Eircom’s fixed-line business.
Under Takeover Panel rules Mr Tony O'Reilly's Valentia consortium now has two weeks to match eIsland's bid, which values the company at €3 billion.
Valentia had been favourite to clinch the deal after agreeing terms with the Eircom board at the beginning of the month. But last week eIsland increased its offer to €1.36 a share.
Today’s move puts pressure on Valentia to top its €2.99 billion (£2.35 billion) offer.
Comsource, the Dutch-Swedish joint venture that owns 35 per cent of Eircom, has given a commitment to accept a lower €2.79 billion bid - or € 1.27 per share - from Valentia. It can break its commitment if a higher offer, which Valentia fails to match, is made.
But the eIsland bid still lacks the support of the Employee Share Ownership Trust (ESOT), which has a 14.9 per cent stake in Eircom.
ESOT and eIsland met yesterday to discuss the bid.