Administrators at BDO said it will begin the process of an orderly wind-down of the business but it will also consider a sale of the firm and is seeking expressions of interest from potential buyers.
Around 400 people and businesses are owed money by the Australian auction house and gallery firm, set up by Sumner and Amanda Swanson in 2004, after it went into administration in December 2017. It has assets of about Aus$3m (£1.7m) and debts of Aus$12m (£7m).
The firm’s primary investor, businessman Jack Gringlas, is thought to be the biggest creditor.
All vendors who have consigned goods to Mossgreen for sale will be contacted and arrangements made for the return of their possessions.
Sumner said a proposed investment plan had not worked out.
He told ATG: “This is personally and professionally devastating to me and my wife because of the effect it is having on staff, creditors and clients.
“We have never traded insolvent and we had an agreed plan following voluntary administration that, due to changing circumstances beyond my control, did not come to fruition.”
Sumner added: “While I have been made redundant, I am continuing to work without pay to ensure that vendors have property returned and creditors are looked after as best as possible.”
BDO said the closure of the business is “extremely disappointing to all parties affected by it. BDO will be working with staff, vendors, creditors and other stakeholders to ensure that the impacts of closure are minimised.”