Intu originally bought a 50 per cent stake in Merry Hill, the seventh largest United Kingdom shopping centre, in March 2014 for £408m from Westfield.
In taking control of Intu, Hammerson will bolster its existing portfolio through the addition of major retail assets such as London's Brent Cross, Birmingham's famous Bullring and Manchester's Trafford Centre.
Liberum said since the combined group will own 13 of the top 20 ranked shopping centres, it may struggle to gain approval by the Competition and Markets Authority.
Although the group will now be called Hammerson plc, Intu will still be keeping their brand.
The new company will retain the Hammerson name and shareholders will vote on the deal next year.
"As clothing and footwear retailers focus on supermalls to create large-scale, experience-led stores, physical retail spend will move away from town centres towards destination shopping centres, ensuring supermall space is hot property", said Sofie Willmott, senior retail analyst at GlobalData.
What could not be agreed was whether this deal benefits Hammerson.
Hammerson, which also owns Bicester Village, will pay 253.9p a share in a deal that values Intu at £3.4bn.
Hammerson also faces the risk an worldwide third party could show interest in making a bid for Intu, the broker said.
Shares in Hammerson dropped 3.5 per cent this morning, while Intu's stock jumped more than 18 per cent.
John Strachan, chairman of Intu, said the deal between the two companies would "present a highly attractive proposition for retailers and shoppers in Europe's leading cities".
Mr Atkins added: "This marks an exciting milestone in the history of Hammerson".
"The acquisition creates a leading pan-European platform of desirable retail and leisure destinations which are better positioned to serve the needs of our retailers, excite our customers and support our partners and communities", Atkins said.
Hammerson estimates pre-tax cost synergies of about £25mln per year in the second year following completion of the takeover.
"Hammerson is one of our preferred United Kingdom retail real estate investment trusts, but this is primarily due to its European diversification, and we continue to remain cautious on the short-and medium-term outlook for the United Kingdom", said Elston.
"The boards of Hammerson and Intu believe that there is a compelling strategic rationale for the acquisition, which will bring together their high-quality retail property portfolios and their combined expertise to create a leading European retail real estate investment trust with a strong income profile and superior growth prospects".