Stephen Lansdown has let go of five and a half million Hargreaves Lansdown shares.
In a statement to the stockmarket it was revealed Lansdown (pictured) sold the shares on Wednesday, bringing his holding below the 19% mark to 18.97%. He retains ninety million shares.
With shares in the FTSE 100 discount broker ending trade at 960.50p, the transaction could have netted the firm's co-founder Lansdown £52.8 million.
Lansdown featured prominently in this weekend's Sunday Times Rich List, a detailed analysis of the wealthiest individuals in Britain.
According to the 2013 survey Lansdown is worth in the region of £900 million, while Peter Hargreaves, who he established the Bristol broker alongside, is worth an estimated £1.5 billion.