While the local market has a November rate hike 90% priced in, the US 10-year Treasury bond has fallen to its lowest level since February.
NZX chief executive Mark Peterson said Benjamin Phillips made a significant contribution to the stock exchange.
The five founder shareholders are still substantial holders after selling nearly 21% last week.
The $9.18m stake will be raised via a placement at a 5% discount to a volume-weighted average.