Shares in Panmure, which is 46 percent owned by Qatari investment bank QInvest, tumbled 18.5 percent to 11 pence.
Linacre said it was the investment banking side Panmure Gordon, which advises clients on acquisitions, fundraising and listings, that had been the worst hit by market havoc, rather than its sales and trading division.
It's a combination of deals just taking longer, financings taking longer, Linacre told Reuters. Commissions (in trading) right across the City (of London) are poor but everyone knows that.
Linacre, who has held the top job for six years and been at the firm for nearly 21 years, will step down by the end of 2012. He will remain on the board and at the firm. The broker said it had started searching for his successor.
Panmure Gordon said market turmoil, sparked by euro zone debt worries that have intensified in the last six months, had delayed a number of sizeable investment banking transactions from the fourth quarter of 2011 into 2012, in Britain and the United States.
The fees generated by those deals should instead feed into 2012 income, Linacre said.
Many firms are also cutting jobs in these areas as they adjust for a leaner period.
The firm said it would make a loss in the second half to add to the first-half loss of 4 million pounds.
Linacre said that despite disrupted markets, Panmure Gordon, which has been adding new corporate clients this year, saw chances to gain more customers -- partly sparking his decision to step aside and focus on client work.
I am a client relationship man by background, Linacre said. There are great opportunities to get out there and win business.
Linacre said Panmure Gordon was keeping a tight lid on costs. There were no plans for new hires or redundancies.
(Reporting by Sarah White; Editing by Hans-Juergen Peters and David Cowell)