Caveat emptor took on a whole new meaning this week with the revelation from Irish Stock Exchange chief executive Tom Healy that the exchange's rules and regulations were there to protect, essentially, everyone except the investor.

This revelation came to light following Tony Spollen's evidence to the DIRT inquiry. According to the former group internal auditor, AIB was faced with a disappointing take-up of shares in an offering on behalf of Dana, an oil exploration company, when it came to the market in 1988. One AIB subsidiary was hired to organise the share placing and another to underwrite the issue.

Coincidentally or otherwise a large number of Dana shares soon afterwards ended up in the possession of parties connected to AIB. Nothing was said then or, indeed, until now about what might to many people seem an exercise in supporting artificially a share price. Any such support might mislead investors about the realistic prospects for any current or future investment in the stock.

In any case the stock exchange was never informed . . . and it now appears there was no obligation for the bank to notify it, which says something for the transparency of Irish share dealings.