Buik said today that he will be leaving the City firm at the end of January. He joined Panmure Gordon in April 2013, having been made redundant from Cantor Index the year before.
Panmure Gordon was bought by Atlas Merchant Capital, Bob Diamond's investment firm, and a Qatari investment firm in April last year for £15.5m.
Buik said the new chief executive, Ian Axe, will offer the "innovative leadership" to steer Panmure Gordon through regulatory changes.
Buik said: "Panmure now has a professional communications service and in my humble opinion Simon French is as good a commentator on economic and financial issues as there is in the City.
"My role at Panmure and therefore contribution has now genuinely become redundant and frankly it is time for me to make way. I am very happy to do so."