The Financial Markets Authority is warning investors in Tower and Dorchester Pacific that the Stock and Share Trading Company may make an unsolicited offer for their shares.
The FMA says it has asked Stock and Share to include a warning on any offer it makes, and it has undertaken to do to so.
The agency says the warning is designed to encourage investors to talk to an authorised financial adviser or sharebroker to find out what their investment is really worth before committing to sell it.
It's also advising that VonWin Capital Management intends to make an offer to bondholders in Irongate Property who have expressed an interest in selling their bonds.
It has also asked VonWin to include a warning in any offer.