The business services group SAI Global is the tip to be the buyer of Perpetual's mortgage servicing business, which the wealth management company is shedding as part of a business transformation.Perpetual announced its plan to sell the mortgage servicing arm of its corporate trustee division at an investor briefing yesterday at which it also outlined plans to simplify its operations, shed 300 staff and find A$50 million in annual cost savings.Perpetual chief executive Geoff Lloyd said the group wanted to get out of the purely administrative type of business, such as mortgage servicing, that put a heavy demand on the IT budget.The firm has also struggled to satisfy banks and other lenders who are its customers, with delays in preparing documents common two years ago. ANZ last year pulled its business from Perpetual only a couple of years after outsourcing the work. ANZ at the time engaged SAI to undertake mortgage settlement services.Perpetual entered the mortgage servicing business five years ago with the takeover of two specialist legal firms. It paid $9 million to acquire the two firms.A letter that Perpetual's group executive for corporate trusts, Chris Green, sent to mortgage servicing customers yesterday said: "This industry is going through a period of change and requires an owner committed to continued investment in IT and business process."Mortgage servicing helped keep Perpetual's trust division growing after the financial crisis but this was at the cost of shrinking margins.Lloyd said Perpetual would continue to offer trustee services in the securitisation market, where it is the market leader. Perpetual won the trustee work for four out of the five covered bond issues this year.Lloyd said securitisation trustee services provided the group with a good annual income stream and did not require a lot of investment. "It is a high return business that is very light on capital," he said.The corporate trust division reported $97.2 million of revenue in 2010/11, of which $54.5 million came from trust services and $42.7 million from mortgage servicing.In the December half, the division suffered a 39 per cent fall in pre-tax profit, half-on-half, as the stock of residential mortgage-backed securities on issue continued to decline and the mortgage servicing business lost a major bank client.The division's earnings margin had fallen from 45 per cent in the 2008/09 financial year to 22 per cent in the December half.Lloyd said the mortgage servicing business's costs this financial year would be $28 million to $30 million.