* Aconex shares rise 45 pct on Oracle offer
* Oracle says transaction should close in first half of 2018
* Aconex subject to break-up fee should deal not proceed (Adds share price reaction, deal timeframe, chairman comment)
By Jonathan Barrett
Sydney, Dec 18 (Reuters) - Australia's Aconex Ltd said on Monday it had received a A$1.56 billion ($1.2 billion), or A$7.80 in cash-per-share, buyout offer from U.S. software major Oracle Corp, sending the target's share price up 45 percent.
Aconex said in a statement its directors unanimously recommended the offer, with shareholders of the cloud-based project management company scheduled to vote on the bid at a scheme meeting in March next year.
The Australian company specialises in web-based project management software that allows input from different teams. Its technology has been used on global projects including the Panama Canal extension.
"Oracle's offer of A$7.80 per share represents a significant premium and a high degree of certainty of value to shareholders through the cash offer and limited conditionality," Aconex Chairman Adam Lewis said in a statement.
Aconex founders Leigh Jasper and Rob Phillpot, who both have holdings of just over 5 percent, declined interview requests on Monday.
The company has experienced massive share price fluctuations since listing in 2014 at A$1.90, and peaking at just above A$8.50 last year.
The share price rose 45 percent immediately after trading resumed on Monday to just below the A$7.80 cash-per-share offer.
Aconex, which focuses on construction projects, said it would be liable to pay Oracle about 1 percent of the deal's equity value as a break-up fee under certain conditions which it did not specify.
Oracle said in a statement that the transaction was expected to close in the first half of 2018.
The proposed transaction was one of two major U.S.-Australian technology deals unveiled on Monday, with Australian data centre provider Metronode receiving a A$1.04 billion ($791.2 million) bid from U.S. company Equinix Inc.
($1 = 1.3074 Australian dollars) (Reporting by Jonathan Barrett in SYDNEY. Additional reporting by Aaron Saldanha in Bengaluru, Editing by Stephen Coates)