His moves around the IAG share register were enough to get the giant insurers hot under the collar. Now investor David Tweed’s latest activities have led the Australian Securities and Investments Commission (ASIC) to warn investors against putting themselves at risk by entering into offers that don’t comply with legal requirements.

ASIC says it has had a 51% increase in calls during the past 12 months regarding unsolicited offers from Mr Tweed’s company, National Exchange Corporation, to buy shareholders’ stakes in companies. Its latest warning identifies shareholders in Axa Pacific Holdings and Tattersall’s as targets.

No one is suggesting Mr Tweed is acting illegally by making unsolicited offers to buy shares, but ASIC Commissioner Professor Berna Collier is keen to have the owners of the shares understand better what they might be getting into. She says it’s “against the law to mislead or deceive shareholders into accepting an offer”.

“The offer must comply with strict legal requirements, including the prohibition against misleading or deceptive or unconscionable conduct,” she said.

More than 10 different entities are understood to be making unsolicited offers to shareholders through mass mail-outs.

 “These offers are on the rise and investors risk losing money by selling their shares for less than they could get on the open market,” Professor Collier said.