Longtime friend Murray Boyte described Gaynor as a fearless champion for the small investor and the right for them to be treated fairly.
His "mighty pen" was required reading and the "high-rolling companies of the 80s felt the full force of its power", Boyte said in a eulogy at a memorial held at St Patrick and St Joseph Cathedral in Auckland today.
"He challenged the lax oversight of the regulatory bodies and the patently inadequate capital market regulation that enabled debt-laden, poorly governed corporates to prosper at the expense of the unsuspecting shareholder. His commentaries and research were prescient. Brian foreshadowed the 1987 sharemarket crash as inevitable."
Gaynor was twice awarded NZ Shareholders Association's Beacon award for services to the investment community.
In 2003 he was one of the founders of Milford Asset Management, arguably this country's most successful KiwiSaver provider.
"For Brian it was not about being different but about his core principles and beliefs. This can no better be seen than in his greatest legacy and love, Milford Asset Management," Boyte said.
"Here was a man who through his commitment, hard work, diligence and vision leaves the New Zealand financial markets in a better shape than when he found them. He will be remembered as a titan of the New Zealand capital markets.
"Anna, Peter, we share your great loss, A wonderful husband, a loving father, a person who could have a meaningful conversation with anyone he met.
"We celebrate with you an extraordinary life of an exceptional person who contributed so much across all facets of society in his adopted country. His memory will live on in his many achievements which have now become his legacy."
The cathedral was filled with Gaynor's family, friends, colleagues and those who followed his popular columns.