QBE plans to adopt a more aggressive financial structure for PMI. The announcement to the market published late yesterday said the insurer would fund the initial cash payment with $522 million in excess capital and $300 million of debt.Neil Drabsch, chief financial officer of QBE, said in an interview that it expected to maintain a capital base for PMI of between $400 million and $500 million. Drabsch said joining PMI with mixed commercial insurance business would allow the firm to adopt a different capital structure while meeting requirements of APRA and ratings agencies.About 45 per cent of QBE's insurance business is long tail, including workers' compensation, professional indemnity and trade credit insurance.As for why target PMI and why now, Drabsch said "PMI were a pressured seller. We got a very, very good price."One measure of the case for selling from PMI's point of view is that the US monoline insurer's market capitalisation is little more than one quarter of the cash windfall it will receive from selling its Australian and Asian businesses.Like many monoline insurers in the US, its financial profile has taken a battering, as has its credit rating.In order to preserve its AA- rating PMI Australia earlier this year agreed not to pay any dividends or repatriate any capital to its owner.Drabsch said QBE would target a return on capital of 20 per cent from PMI. QBE said in its statement to the ASX that the acquisition would be earnings per share accretive from the first year.QBE said it expected the acquisition to close next month.