The offer was made on 11 June and was for all the shares in the company at $4.85 a share, meaning that the total bid would come to a shade over $3 billion.
AGL managing director and chief executive Brett Redman said in a statement to the ASX on Monday: “AGL is exploring investment opportunities across three focus areas: optimising our existing portfolio for performance and value, evolving and expanding our core energy markets offerings, and creating new opportunities with connected customers.
“We believe there will be material opportunities for AGL as energy and data value streams continue to converge and the traditional energy sector accelerates its transformation.
“However, we are no longer confident that an acquisition of Vocus at the proposed terms would represent sufficient certainty of creating value for AGL shareholders. We would like to thank the Vocus board and management team for their assistance over recent weeks.”
Vocus chief executive Kevin Russell commented: “As we have repeatedly said, this is a three-year turnaround. We have great confidence that our strategy and ability to execute our business plan will deliver significant value to our shareholders in the medium to long term.
"There is growing demand for our strategically valuable network assets and we have a substantial opportunity for Vocus Networks to gain market share. This is the core of our business. The Vocus management team will now be able to focus all of their attention on realising the opportunity that we have ahead of us.”
AGL had made a bid to buy Vocus last month, but backed out on 31 May when the terms of due diligence could not be agreed.
Prior to that, Swedish equity firm EQT Infrastructure pulled out of a bid for Vocus that valued the company at $3.3 billion or $5.25 a share.
In June 2017 a report said TPG Capital could team up with Vocus founder James Spenceley to examine a takeover in the event that the equity firm's bid for Fairfax Media did not come off.
The same month, American equity firm Kohlberg Kravis Roberts made a bid to buy Vocus for A$2.2 billion.
Vocus has been hit by the ever-decreasing margins of its broadband business as the NBN Co has made it difficult for RSPs to turn a profit. Its retail business was written down by about $1 billion in 2017.