Tweed's business practices are controversial in some quarters and his success has attracted criticism from the media and the Australian Securities & Investments Commission.
It transpired that Tweed had assumed the same name as a former business journalist and later sharemarket analyst who had an extended working stay in Europe.
According to the Herald Sun, Tweed lived in a de facto relationship with Donna Newman for 22 years before they married on 23 June 2018, in Las Vegas; they also have three children together.
The Sun also alleges that "Mr Tweed has been ostracised by his family, who have begged him to stop his unscrupulous behaviour" but is defended by Ms Newman's father Dennis, who has said that, In Australia, there is a high proportion of share ownership by less sophisticated investors.
Companies such as Insurance Australia Group (IAG) and AMP, Axa, Tower, IOOF, OFM Investments, Aevum have demutualised and in the process given shares to the former (mutual) policyholders.
A large number of shareholders, often elderly people who had never owned shares before, would take up the offer despite the market price clearly available in newspapers such as the Sydney Morning Herald and Australian Financial Review.
Several shareholders who had accepted Tweed's offers annulled the contract due to technicalities in the off-market transfer process; however, the great proportion were relieved of their shares.
Whenever a technicality has been identified, Tweed has amended his practices to stay one step ahead of the law, thus frustrating those[who?]
These cases are usually settled in his favour and also enable the former shareholders to avoid the legal costs of mounting a defence.
Companies have tried to close their share registers, citing National Privacy Principles (NPP) or providing them in a non-machine readable form (to make it difficult for Tweed to easily create offer letters[7]); a court case in 2003 required that all offers that Tweed advanced would need to attach the last known market price of the shares in question.
In September 2003, the Supreme Court of Victoria found that Tweed's offer to purchase shares from investors in OneSteel was deceptive.
At the time the accounting group KPMG calculated that this valued the shares at just 78 cents in today's dollars.
[clarification needed] In his ruling, Justice Robert Osborne stated that the National Exchange acceptance form was so worded that before it could enforce a binding contract on people tempted by low-ball purchase offers, they had to send in the shareholder registration number as well as the signed form before the deadline set out in the offer.
[11] However, this attempt was halted by ASIC in August 2006, who raised "serious objections to the way the bid was structured" by Australian Share Purchasing Company Pty Ltd (ASPC).
In a letter dated 11 November 2007, Tweed's company, Colonial Capital Corporation, offered to buy BHP Billiton shares at a price of $42.47.
In March 2011, Justice White of the Supreme Court of New South Wales found that fund manager Perpetual was justified in double-checking with shareholders before processing transfers, part of its fiduciary duties as the responsible entity.