Mr Kahn has a 25-year association with the charity, serving as a trustee, fundraising committee chair and a member of the corporate service committee.
He had joined Deloitte in 2001 after two decades at PWC and is stepping down as head of financial advisory practice in Europe, three months after taking the role.
Deloitte said Mr Kahn was leaving the firm in August to set up an investment fund around distressed assets and that his departure was not related to the Comet investigation.
A statement to The Times said: "Neville Kahn is leaving the firm to set up an investment fund.
“This is something he has considered for some time and is unrelated to the Comet insolvency or any investigation by the institute."
Mr Kahn is one of the UK's leading insolvency practitioners who has generated over £25 million in fees from the collapse of Woolworths, HMV and Comet.
After being appointed Norwood chair, Mr Kahn said he wanted the charity to continue supporting “those who most desperately need it”.
