A growing trend for the leaking of sensitive financial information in Australian media has drawn the ire of a shareholders' body and stock exchange regulator.
A number of big-money deals and speculation about potential takeovers and capital raising have popped up in Australian media, notably the Australian Financial Review, well-before being made public on the local stock exchange.
Shareholders' Association's chief executive Oliver Mander said the practice was creating an uneven playing field for retail investors who relied on being fairly and equally informed about developments in investment markets.
The AustralianSuper bid for Infratil last year was a good example of how leaks hurt retail investors, as the information was released on an Australian news website behind a paywall late in the afternoon but not disclosed to the local market, he said.
"If you're a seller in that situation you are making your investment decision based on readily available public information and if you haven't got that information at hand you are potentially selling your shares at a lesser value than what they are actually worth.
"That is real money flowing out the door and benefiting someone who does have inside information."
Such leaks were incredibly difficult to police because local regulators had no jurisdiction in Australia, Mander said.
"Somewhat unfortunately being the little sibling in this case does not help us when it comes to lobbying the fat brother across the Tasman."
It would work with the Australian Shareholder's Association to put pressure on their finance sector to improve the culture around disclosing sensitive market information, he said.
The NZX's regulatory arm NZ RegCo slammed what it called a "growing culture of information leaks" but acknowledged there is limited action it could take".
Chief executive Joost van Amelsfort said: "Those seem to occur either when competitive multi-party negotiations are on foot or where parties adopt these tactics to get negotiating leverage through the media or to try and force a desired commercial outcome".
It was limited in what it could do but would act, where possible, to lessen the impact, he said.
"If necessary, we will place an issuer into a trading halt to manage their disclosure obligations in these circumstances."