The head of the stock market Mark Weldon says he would be concerned if there was a wider trend to limit the media's ability to cover annual meetings.
Vector and PGG Wrightson banned recording at their shareholder gatherings recently, with Vector chairman's Michael Stiassney saying he wanted to avoid a media circus.
PGG Wrightson chairman Keith Smith denied the move was driven by a desire to quell publicity of shareholder anger about the loss in value as the company struggles under a mountain of debt.
Mr Weldon says companies are free to restrict media coverage, but says there is research that greater transparency helps firms raise capital.
He says a University of Chicago study about three months ago looked at what broad dissemination of company information and news did to a company's cost of capital or its share price.
Mr Weldon says it found that the broader coverage a company had, the better the company's cost of capital.
He says getting information out there plays a very valuable role in markets.
Mr Weldon says would prefer more media and business analysis, not less.