Prosser, who left the investment bank this April, has named his new enterprise Prosser Associates, and
already counts his former employer as a client.
Initially, he will use a ‘virtual' network of freelance consultants to work on specific projects.
Prosser Associates plans to work alongside larger financial agencies on M&A deals and comms for organisations that are integrating.
‘Hedge funds and private equity groups are beginning to act like big businesses,' explained Prosser, adding: ‘I'm hoping they'll find my experience useful within the investment sphere.'
Before joining Lehman Brothers in 2001, Prosser was director of corporate affairs at AXA UK, corporate affairs director at the Guardian Royal Exchange, and head of PR in the corporate and institutional banking division of the Royal Bank of Scotland.
He began his career as a financial analyst at Chase Manhattan in the mid-1980s, after a stint as a trumpet player in Paul Weller's post-Jam outfit The Style Council. He is also a former chairman of the CIPR's Corporate and Financial Group.
The 47-year-old suffered a heart attack two years ago but says he is now recovered and has been planning the launch for the past few months.
Prosser's role at Lehman Brothers has been partially assumed by former Financial Times editor Andrew Gowers. He took on the new post of head of corporate comms, advertising and brand and marketing strategy for Europe in June to aid Lehman Brothers' ambitious plans across the Continent.
Lehman's PR department was overseen by Europe and Asia executive director of corporate comms Christine Chinnery after Prosser fell ill.