Banksia Securities Limited, a $1 billion mortgage fund manager, called in the receivers yesterday, after a review by its new chief executive revealed many more problem loans than previously acknowledged.Directors posted a notice on the company's website yesterday disclosing a "material increase" in provisions required to cover impaired loans.It said the "likely increase… will result in the company having negative net equity."McGrath Nicol took over as receivers in the afternoon.Warren Shaw began work as Banksia's CEO in May. He joined the Goulburn Valley-based group from National Australia Bank. Shaw replaced Patrick Godfrey, who remains a director.Banksia had reported a profit of A$882,000 for the year to June 2012 (down by $1 million on 2011) when directors signed off the accounts on September 27.The bad debt charge had increased to $2.4 million, from $900,000 the year before.The group now expects to write off at least another $24 million in bad loans (the stated net assets at June 30).Banksia had $500 million in loans as assets at the end of the financial year and $134 million in cash.Investors in debentures - or "secured notes" - provided $662 million in funding. The Trust Company is the secured creditor of Banksia Securities on behalf of the investors.Banksia Mortgage Fund - an associated entity - managed $150 million in loans funded by $158 million provided by investors. There was no mention in the notices on the Banksia website yesterday on the implications for the mortgage fund, which is bound to receive many requests for withdrawals.Banksia joins a long line of unlisted "income" fund managers in Australia whose businesses have proven marginal or unviable over the five years of the financial crisis.Morningstar refers to this list as comprising "thawing" mortgage, property and high-yield managed funds (as opposed to "frozen funds", though some are frozen) since most allow restricted redemptions.