The country's chief financial watchdog says Christchurch businessman Bernard Whimp deliberately misled investors when he made offers to tens of thousands of shareholders.
In March, Mr Whimp and his companies made a series of offers to about 130,000 shareholders of six listed companies.
The Financial Markets Authority told the High Court in Wellington on Monday that the offer gave the impression the payment for shares would be made either immediately or promptly.
But in the offer's fine print, the authority says, investors were told they would be paid in instalments over 10 years, with Mr Whimp receiving the share dividends during that time.
Mr Whimp's lawyer, Nicholas Till QC, wouldn't concede that his client's behaviour was misleading but didn't oppose the authority's suggestion that it was.
He said his client should be able to write to those who have already accepted to give them another chance to confirm they want to sell.
Earlier, the Securities Commission also told the court that Mr Whimp's offer was misleading because it gave the impression of prompt payment for the shares and it wasn't made clear that the length of time over which payment would be made effectively undervalued the shares.
Justice Warwick Gendall has reserved his decision and extended an interim injunction stopping any shares changing hands under the offers until his decision is released.